Search found 17913 matches

by Chem_Mod
Thu Aug 25, 2011 10:56 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Period 2 group 1-2 and 6-7 patterns?
Replies: 1
Views: 211

Period 2 group 1-2 and 6-7 patterns?

Question: For period 2, Groups 1-5 (pi 2p bonds come first after 2s*) and Groups 6-7 (sigma 2p comes first instead). Do these patterns apply for the valence electron configurations for the period 3 elements below them, or is there a complication because of the possibility of d-orbitals in an expand...
by Chem_Mod
Thu Aug 25, 2011 10:56 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: What is exception when the 3d orbitals are lower than 4s?
Replies: 1
Views: 334

Re: What is exception when the 3d-orbitals lower than 4s?

Answer: In general, the 3d orbitals are lower in energy than the 4s orbital, which is why the 4s orbital is always filled before the electrons are placed in the 3d orbitals (if you think about it in terms of the Aufbau, or "building up principle"). The exceptions are chromium and copper. ...
by Chem_Mod
Thu Aug 25, 2011 10:55 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: What is exception when the 3d orbitals are lower than 4s?
Replies: 1
Views: 334

What is exception when the 3d orbitals are lower than 4s?

Question: What is the exception when the 3d-orbitals would be lower than the 4s-orbitals? Also, what results in half full d^5 subshell?
by Chem_Mod
Thu Aug 25, 2011 10:54 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Are there exceptions to the order of filling?
Replies: 1
Views: 257

Re: Are there exceptions to the order of filling?

Answer: Copper is an exception to the normal manner of writing electron configurations: it is ([Ar]3d10 4s1). When it loses one electron (Cu+ has net positive charge of 1, resulting from the loss of 1 electron) it loses it from the 4s orbital, because these orbitals are furthest from the nucleus an...
by Chem_Mod
Thu Aug 25, 2011 10:53 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Are there exceptions to the order of filling?
Replies: 1
Views: 257

Are there exceptions to the order of filling?

Question: When writing electron configurations, how come sometimes there is a configuration like [Ar]3d10 instead of 3d8 4s2. Are there exceptions to the order of filling?
by Chem_Mod
Thu Aug 25, 2011 10:53 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How to figure out the number of valence electrons in metals?
Replies: 1
Views: 364

Re: How to figure out the number of valence electrons in met

Answer: This is dependent of the atom you are considering. If for instance you are looking at the transition metals, then the outer most electrons are those in the s and d orbitals. In that case, the number of s and d electrons will be your valence electrons. If you were looking at p block elements...
by Chem_Mod
Thu Aug 25, 2011 10:53 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How to figure out the number of valence electrons in metals?
Replies: 1
Views: 364

How to figure out the number of valence electrons in metals?

Question: How do we figure out the number of valence electrons in metals? They seem to be variable.
by Chem_Mod
Thu Aug 25, 2011 10:52 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence e- configuration = Ground state e- configuration?
Replies: 1
Views: 219

Re: valence e- configuration= a ground state e- configuratio

Answer: The valence electron configuration would only require you to say the valence electrons (outermost shell). The ground state electron configuration would require all electrons which can either be written with all orbitals or the noble gas preceding the row in question then the valence electro...
by Chem_Mod
Thu Aug 25, 2011 10:52 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence e- configuration = Ground state e- configuration?
Replies: 1
Views: 219

Valence e- configuration = Ground state e- configuration?

Question: Is the valence electron configuration the same as a ground state electron configuration?
by Chem_Mod
Thu Aug 25, 2011 10:50 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: electron configuration of both N2 and F2?
Replies: 1
Views: 8366

Re: electron configuration of both N2 and F2?

Answer: F2 the following: (sigma 2s)^2. (sigma 2s*)^2. (sigma 2px)^2. (pi 2py)^2. (pi 2pz)^2. (pi 2px*)^2. (pi 2py*)^2.

N2 the following: (sigma 2s)^2. (sigma 2s*)^2. (pi 2px)^2. (pi 2py)^2. (sigma 2pz)^2.
by Chem_Mod
Thu Aug 25, 2011 10:50 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: electron configuration of both N2 and F2?
Replies: 1
Views: 8366

electron configuration of both N2 and F2?

Question: What is the electron configuration of both N2 and F2, including the x, y, and z of the p-orbitals?
by Chem_Mod
Thu Aug 25, 2011 10:49 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How does Cr2+ has 4 unpaired electrons?
Replies: 1
Views: 12154

Re: How does Cr2+ has 4 unpaired electrons?

Answer: The electron configuration for Cr is [Ar]3d6 4s2 (note that 4s is higher in energy than 3d - that is important). Cr2+ means we remove 2 electrons, and we remove them from the highest energy level, which is 4s, so the electron configuration for Cr2+ is [Ar]3d6. The d orbital has 5 orbitals a...
by Chem_Mod
Thu Aug 25, 2011 10:49 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How does Cr2+ has 4 unpaired electrons?
Replies: 1
Views: 12154

How does Cr2+ has 4 unpaired electrons?

Question: How does Cr2+ has 4 unpaired electrons? How do you tell in general?
by Chem_Mod
Thu Aug 25, 2011 10:49 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Cadmium's s and d orbitals are filled, how does Cd2+ exist?
Replies: 1
Views: 236

Re: Cadmium's s and d orbitals are filled, so why there's Ca

Answer: The two 5s e- are removed. Just like Ca or Mg losing two s e- to form Ca2+ and Mg2+. They are all metals.
by Chem_Mod
Thu Aug 25, 2011 10:48 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Cadmium's s and d orbitals are filled, how does Cd2+ exist?
Replies: 1
Views: 236

Cadmium's s and d orbitals are filled, how does Cd2+ exist?

Question: I would think that Cadmium would not become an ion since its s and d orbitals are filled, so why is it possible for Cd2+ to exist?
by Chem_Mod
Thu Aug 25, 2011 10:47 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: what would the electron config. of Cu2+ be?
Replies: 1
Views: 9880

Re: what would the electron config. of Cu2+ be?

Answer: Since the electron configuration of Cu is [Ar]3d10 4s1, then Cu2+ is [Ar]3d9.
by Chem_Mod
Thu Aug 25, 2011 10:47 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: what would the electron config. of Cu2+ be?
Replies: 1
Views: 9880

what would the electron config. of Cu2+ be?

Question: Since we know that the electron configuration of Cu is [Ar]3d10 4s1, what would the electron config. of Cu2+ be?
by Chem_Mod
Thu Aug 25, 2011 10:47 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state electron configuration of Cu+?
Replies: 1
Views: 4593

Re: ground state electron configuration of Cu+ ?

Answer: As ground state for Cu is [Ar]3d10 4s1, ground state for Cu+ is [Ar]3d10 because we remove the last e- to make the cation.
by Chem_Mod
Thu Aug 25, 2011 10:46 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state electron configuration of Cu+?
Replies: 1
Views: 4593

Ground state electron configuration of Cu+?

Question: Why is the ground state electron configuration of Cu+ equal to [Ar]3d^10 instead of [Ar]3d8 4s2? I thought that electrons were taken from the s orbital to fill a d orbital only if there are 4 or 9 electrons in the d orbital.
by Chem_Mod
Thu Aug 25, 2011 10:46 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: full electron configuration for Cr+ ?
Replies: 1
Views: 11870

Re: full electron configuration for Cr+ ?

The valence electron configuration of Cr is 1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s1 instead of 1s2, 2s2, 2p6, 3s2, 3p6, 3d4, 4s2 because one of the electron from the s orbital jumped to the d orbital. By distributing its electrons along the empty orbitals, it becomes more stable. Since the ground state fo...
by Chem_Mod
Thu Aug 25, 2011 10:45 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: full electron configuration for Cr+ ?
Replies: 1
Views: 11870

full electron configuration for Cr+ ?

The full electron configuration for Cr+. The answer was 1s2, 2s2, 2p6, 3s2, 3p6, 3d5. Shouldn't it be 1s2, 2s2, 2p6, 3s2, 3p6, 3d3, 4s2 instead?
by Chem_Mod
Thu Aug 25, 2011 10:45 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: take out an e- from the 5p before the 5s for In+?
Replies: 1
Views: 263

Re: take out an e- from the 5p before the 5s for In+?

Answer: Since the electrons in 5p have higher energy than the electrons in 5s, the electrons in 5p is removed first. It is no different from why we would remove electrons from the 3p before the 3s orbital.
by Chem_Mod
Thu Aug 25, 2011 10:45 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: take out an e- from the 5p before the 5s for In+?
Replies: 1
Views: 263

take out an e- from the 5p before the 5s for In+?

Question: Why do you take out an e- from the 5p before the 5s when you did the electron configuration of In+?
by Chem_Mod
Thu Aug 25, 2011 10:44 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How to write the electron configuration of a metal cation
Replies: 1
Views: 199

Re: Electron configuration of a metal cation

Answer: First write the e- configuration for the neutral atom. Then remove the last e- that you wrote to get the appropriate e- configuration for the cation.
by Chem_Mod
Thu Aug 25, 2011 10:44 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How to write the electron configuration of a metal cation
Replies: 1
Views: 199

How to write the electron configuration of a metal cation

Question: How do you write the electron configuration of a metal cation?
by Chem_Mod
Thu Aug 25, 2011 10:42 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration for Ag: Ordering 4d and 5s
Replies: 1
Views: 410

Re: Electron configuration for Ag

The 5s should come after the 4d. Once the d orbitals gain electrons, the d orbitals become lower in energy than the 5s, so we list the d orbitals first (since we list the orbitals from lowest to highest energy).
by Chem_Mod
Thu Aug 25, 2011 10:42 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration for Ag: Ordering 4d and 5s
Replies: 1
Views: 410

Electron configuration for Ag: Ordering 4d and 5s

Question: Why is the e- configuration for Ag [Kr]4d10 5s1 not [Kr]5s1 4d10? Which is written first?
by Chem_Mod
Thu Aug 25, 2011 10:41 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valance electrons for d-orbital
Replies: 2
Views: 228

Re: Valance electrons for d-orbital

Answer: Count the # of e- in the s- and d- orbitals for the outer shell. Chromium would have 6 valence electrons.
by Chem_Mod
Thu Aug 25, 2011 10:41 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valance electrons for d-orbital
Replies: 2
Views: 228

Valance electrons for d-orbital

Question: How would we determine the number of valence electrons for an element in the d-block (transition elements)? For instance, how many valence are there for Chromium?
by Chem_Mod
Thu Aug 25, 2011 10:40 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How do you find valence electrons?
Replies: 1
Views: 325

Re: How do you find valence electrons?

Answer: Valence electrons are the electrons in the outermost shell of the atom, that is the electrons with the highest principle quantum number. For instance Carbon has electrons in the n=2 shell. The electrons in this shell are the valence electrons. Specifically, it has two electrons in the 2s su...
by Chem_Mod
Thu Aug 25, 2011 10:40 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How do you find valence electrons?
Replies: 1
Views: 325

How do you find valence electrons?

Question: How do you find valence electrons?
by Chem_Mod
Thu Aug 25, 2011 10:40 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: (n-1) d-electrons of d-block elements as valence electrons?
Replies: 1
Views: 353

Re: (n-1)d-electrons of d-block elements as valence electron

Answer: Yes, you should consider the (n-1) d-electrons of d-block elements as valence electrons. Cr has 6 valence e-. Count the e- from the previous noble gas.
by Chem_Mod
Thu Aug 25, 2011 10:39 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: (n-1) d-electrons of d-block elements as valence electrons?
Replies: 1
Views: 353

(n-1) d-electrons of d-block elements as valence electrons?

Question: Do you consider the (n-1) d-electrons of d-block elements as valence electrons? How many valence electrons does Cr have?
by Chem_Mod
Thu Aug 25, 2011 10:39 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: For a ground state configuration, when is a f-orbital used?
Replies: 1
Views: 228

Re: For a ground state configuration, when is a f-orbital us

Answer: f-orbitals are used in periods 6 & 7. We covered the filling of f-orbitals (Lanthanides and Actinides).
by Chem_Mod
Thu Aug 25, 2011 10:39 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: For a ground state configuration, when is a f-orbital used?
Replies: 1
Views: 228

For a ground state configuration, when is a f-orbital used?

Question: For a ground state configuration, when is a f-orbital used?
by Chem_Mod
Thu Aug 25, 2011 10:38 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron config. written with d orbital, excluding s?
Replies: 1
Views: 181

Re: why electron confi are written with d orbital,excluding

Answer: Electron configurations are only written without the s orbitals if you are talking about a transition metal ion which has already lost the electrons in the s orbital. There are special cases (see the column with Cr and Cu) where a single s electron can be promoted to the d orbital.
by Chem_Mod
Thu Aug 25, 2011 10:38 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron config. written with d orbital, excluding s?
Replies: 1
Views: 181

Electron config. written with d orbital, excluding s?

Question: Could you explain why electron configurations are written with the d orbital, excluding the s orbital (whose electrons are added to the preceding d orbital). Do you always transfer the electrons from the s orbital into the d orbital?
by Chem_Mod
Thu Aug 25, 2011 10:37 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Don't count the d-orbital electrons as valence electrons?
Replies: 1
Views: 2733

Re: don't count the d-orbital electrons as valence electrons

Answer: Count only the electrons in the same shell, that is, the outermost shell. For Xe and Br the s and p electrons are in the same shell, but d electrons are not in the outermost shell.
by Chem_Mod
Thu Aug 25, 2011 10:37 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Don't count the d-orbital electrons as valence electrons?
Replies: 1
Views: 2733

Don't count the d-orbital electrons as valence electrons?

Question: Is it just a general rule that you don't count the d-orbital electrons as valence electrons for elements in the p-orbitals? For example, Xe has 8 valence e- rather than 18. Would the element Br only have 7 valence electrons, rather than 17? If this is so, what is the reason?
by Chem_Mod
Thu Aug 25, 2011 10:36 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: why 4S orbital is filled first than 3d orbital?
Replies: 1
Views: 380

Re: why 4S orbital is filled first than 3d orbital?

Answer: The 4s is lower in energy than the 3d due to its shape and it has e- density closer to the nucleus.
by Chem_Mod
Thu Aug 25, 2011 10:36 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: why 4S orbital is filled first than 3d orbital?
Replies: 1
Views: 380

why 4S orbital is filled first than 3d orbital?

Question: For electron configurations, why is the 4S orbital filled first than the 3d orbital? Is this connected to orbital's shapes or electron repulsion?
by Chem_Mod
Thu Aug 25, 2011 10:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: [Rn]7s2 6d2 or [Rn]6d2?
Replies: 1
Views: 724

Re: [Rn]7s2 6d2 or [Rn]6d2?

Answer: The two are technically the same, in that they both state that there are 2 electrons in the 7s subshell and the 6d2 subshell. There is a difference in nomenclature as to how to order the orbitals, whether they should be in increasing principle quantum number ([Rn]6d2 7s2) or the way in whic...
by Chem_Mod
Thu Aug 25, 2011 10:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: [Rn]7s2 6d2 or [Rn]6d2?
Replies: 1
Views: 724

[Rn]7s2 6d2 or [Rn]6d2?

Question: Does it matter whether an electronic configuration is written as [Rn]7s2 6d2 or [Rn]6d2?
by Chem_Mod
Thu Aug 25, 2011 10:35 am
Forum: Quantum Numbers and The H-Atom
Topic: How many orbitals are there for n=5?
Replies: 1
Views: 38459

Re: How many orbitals are there for n=5?

Answer: For n=5 we can have l=4, 3, 2, 1, and 0. For each l, we have ml ranging from -l to l. The total number of ml will tell us the number of orbitals. l=4, ml=-4,-3,-2,-1,0,1,2,3,4 for a total of 9 / l=3, ml=-3,-2,-1,0,1,2,3 for a total of 7 / l=2, ml=-2,-1,0,1,2 for a total of 5 / l=1, ml=-1,0,...
by Chem_Mod
Thu Aug 25, 2011 10:34 am
Forum: Quantum Numbers and The H-Atom
Topic: How many orbitals are there for n=5?
Replies: 1
Views: 38459

How many orbitals are there for n=5?

Question: How many orbitals are there for n=5?
by Chem_Mod
Thu Aug 25, 2011 10:34 am
Forum: Quantum Numbers and The H-Atom
Topic: difference between electron orbital and electron subshell?
Replies: 2
Views: 385

Re: difference between electron orbital and electron subshel

Answer: The orbital is determined by the ml value while the subshell is determined by the l value. So if a question asks you how many orbitals there are, it's basically asking how many ml values you can have.
by Chem_Mod
Thu Aug 25, 2011 10:34 am
Forum: Quantum Numbers and The H-Atom
Topic: difference between electron orbital and electron subshell?
Replies: 2
Views: 385

difference between electron orbital and electron subshell?

Question: What is the difference between an electron orbital and an electron subshell?
by Chem_Mod
Thu Aug 25, 2011 10:32 am
Forum: Quantum Numbers and The H-Atom
Topic: What is the pattern for angular momentum quantum numbers?
Replies: 1
Views: 348

Re: What is the pattern for angular momentum quantum numbers

Answer: s orbital means zero angular momentum, p orbital means angular momentum 1, d orbital means angular momentum 2, f orbital means angular momentum 3, and so on
by Chem_Mod
Thu Aug 25, 2011 10:31 am
Forum: Quantum Numbers and The H-Atom
Topic: What is the pattern for angular momentum quantum numbers?
Replies: 1
Views: 348

What is the pattern for angular momentum quantum numbers?

Question: What is the pattern for angular momentum quantum numbers when the orbital is given?
by Chem_Mod
Thu Aug 25, 2011 10:31 am
Forum: Quantum Numbers and The H-Atom
Topic: How many subshells there are in the shell n=4?
Replies: 1
Views: 8669

Re: How many subshells there are in the shell n=4?

Answer: There are 4 subshells: 4s, 4p, 4d, and 4f. When the question asks you about how many subshells there are in a certain shell, what it basically is asking is how many different values of l there are. So if n=4, l can only be 0,1,2,3, which corresponds to s,p,d,f.
by Chem_Mod
Thu Aug 25, 2011 10:31 am
Forum: Quantum Numbers and The H-Atom
Topic: How many subshells there are in the shell n=4?
Replies: 1
Views: 8669

How many subshells there are in the shell n=4?

Question: How many subshells there are in the shell n=4?
by Chem_Mod
Thu Aug 25, 2011 10:30 am
Forum: Quantum Numbers and The H-Atom
Topic: What does the magnetic quantum number find?
Replies: 2
Views: 331

Re: What does the magnetic quantum number find?

Answer: It does not find anything. It simply labels the individual orbitals in a given subshell. All four quantum numbers are meant to designate the identity of an electron in an atom.
by Chem_Mod
Thu Aug 25, 2011 10:30 am
Forum: Quantum Numbers and The H-Atom
Topic: What does the magnetic quantum number find?
Replies: 2
Views: 331

What does the magnetic quantum number find?

Question: What does the magnetic quantum number find?
by Chem_Mod
Thu Aug 25, 2011 10:30 am
Forum: *Particle in a Box
Topic: What is a one dimensional box in regard to a box?
Replies: 1
Views: 472

Re: What is a one dimensional box in regard to a box?

Answer: The one dimensional box means that the particle can only move left or right (in 1-D, in other words, just a line). The distance in which it can move left or right before it hits the walls is L. In other words, the particle in confined within these two walls with a distance of L that it can ...
by Chem_Mod
Thu Aug 25, 2011 10:29 am
Forum: *Particle in a Box
Topic: What is a one dimensional box in regard to a box?
Replies: 1
Views: 472

What is a one dimensional box in regard to a box?

Question: What is a one dimensional box in regards to a particle in a box?
by Chem_Mod
Thu Aug 25, 2011 10:29 am
Forum: *Shrodinger Equation
Topic: Schrodinger equation manipulation and second derivative
Replies: 1
Views: 477

Re: Schrodinger equation manipulation and second derivative

Answer: We did an example of using a wave function in the Schrodinger equation to see what result was obtained for the energy of an electron in an atom. In this example the Schrodinger equation gives us an expression for the energy of an electron. Second derivative is part of the Schrodinger equati...
by Chem_Mod
Thu Aug 25, 2011 10:29 am
Forum: *Shrodinger Equation
Topic: Schrodinger equation manipulation and second derivative
Replies: 1
Views: 477

Schrodinger equation manipulation and second derivative

Question: Does the Schrodinger equation manipulation show that the wave and particle models match up? What does the Schrodinger equation tell us? Why do we take the second derivation of the wave function?
by Chem_Mod
Thu Aug 25, 2011 10:28 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Equality sign in the uncertainty equation?
Replies: 1
Views: 218

Re: equals sign in the uncertainty equation?

Answer: Use the equal sign to represent the lower limit.
by Chem_Mod
Thu Aug 25, 2011 10:27 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Equality sign in the uncertainty equation?
Replies: 1
Views: 218

Equality sign in the uncertainty equation?

Question: Sometimes the uncertainty equation has an equal sign instead of of a greater than or equal sign. Is this a typo or is there a reason behind this?
by Chem_Mod
Thu Aug 25, 2011 10:27 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: plus or minus 1.0 mm per second for the speed. Why x2?
Replies: 1
Views: 286

Re: plus or minus 1.0 mm per second for the speed. Why x2?

Answer: We are interested in the spread when we calculate delta(x) or delta(p). The plus/minus 1 mm/s tells us that if are speed was 15 mm/s, then the possible values would be between 15-1 and 15+1, or 14-16 mm/s. That means there is a 2 mm/s uncertainty in our speed. If it was plus/minus 3, then y...
by Chem_Mod
Thu Aug 25, 2011 10:27 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: plus or minus 1.0 mm per second for the speed. Why x2?
Replies: 1
Views: 286

plus or minus 1.0 mm per second for the speed. Why x2?

Question: The uncertainty principle and what it means when it says plus or minus 1.0 mm per second for the speed. Why do they multiply this by 2? If it were plus or minus 3.0 mm per second, would it be multiply it by 6 (because it's the spread)?
by Chem_Mod
Thu Aug 25, 2011 10:26 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: delta(p) x delta(v)=h/(4xpi), why multiply delta v by 2?
Replies: 1
Views: 522

Re: delta px delta v=h/(4xpi), why multiply delta v by 2?

Answer: The Heisenberg indeterminacy principle uses calculations based on indeterminacy, which is twice the uncertainty, or in other words the spread of the uncertainty. For instance, say we had a velocity measurement of 2.00 +/- 0.01 m/s. The spread of possible values for velocity range from 1.99 ...
by Chem_Mod
Thu Aug 25, 2011 10:25 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: delta(p) x delta(v)=h/(4xpi), why multiply delta v by 2?
Replies: 1
Views: 522

delta(p) x delta(v)=h/(4xpi), why multiply delta v by 2?

Question: For the equation of Heisenberg's uncertainty principle: delta(p) x delta(v)=h/(4xpi), why do we multiply the delta(v) by two to get the correct answer?
by Chem_Mod
Thu Aug 25, 2011 10:25 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Book uses h-bar/2 instead of h/4pi, which is right?
Replies: 1
Views: 318

Book uses h-bar/2 instead of h/4pi, which is right?

Answer: The textbook uses h-bar, which is h with a little line across the top of it.
h-bar just means h/2pi, so h/4pi is the same as (h-bar)/2.
by Chem_Mod
Thu Aug 25, 2011 10:24 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Book uses h-bar/2 instead of h/4pi, which is right?
Replies: 1
Views: 318

Book uses h-bar/2 instead of h/4pi, which is right?

Question: In the Heisenberg's indeterminacy equation the book uses h-bar/2 instead of h/4pi, which you stated in the course reader. Could you please clarify which is the correct one?
by Chem_Mod
Thu Aug 25, 2011 10:23 am
Forum: DeBroglie Equation
Topic: possible use E=(1/2)mv^2 equation to find the wavelength?
Replies: 1
Views: 321

Re: possible useE=(1/2)mv^2 equation to find the wavelength

Answer: E=(1/2)mv^2 applies to particles with static mass, for example an electron or a base ball. So it cannot be used on photons. E=h(frequency) is valid only for photons. To calculate frequency of electrons or particles other than photons, you must use de Broglie relationship. c=(wavelength x fr...
by Chem_Mod
Thu Aug 25, 2011 10:23 am
Forum: DeBroglie Equation
Topic: possible use E=(1/2)mv^2 equation to find the wavelength?
Replies: 1
Views: 321

possible use E=(1/2)mv^2 equation to find the wavelength?

Question: Would it be possible to use the E=(1/2)mv^2 equation to find the wavelength by substituting E=h(frequency) and c= (wavelength x frequency) instead of using the de Broglie relationship? If not, why is this not possible?
by Chem_Mod
Thu Aug 25, 2011 10:22 am
Forum: DeBroglie Equation
Topic: Broglie relation, all particles have wavelike properties?
Replies: 1
Views: 343

Re: Broglie relation, all particles have wavelike properties

Answer: Actually, electrons do have mass. Its mass is 9.11*10^-31 kg. All waves have particle-like properties, but some not in the sense that you would normally think of for a particle. Like for example, photons (which are light waves) have no "rest mass", which means they have no mass th...
by Chem_Mod
Thu Aug 25, 2011 10:22 am
Forum: DeBroglie Equation
Topic: Broglie relation, all particles have wavelike properties?
Replies: 1
Views: 343

Broglie relation, all particles have wavelike properties?

Question: From the de Broglie relation, all particles have wavelike properties, but all waves don't have particle-like properties, right? (i.e. electron lacks mass).
by Chem_Mod
Thu Aug 25, 2011 10:21 am
Forum: DeBroglie Equation
Topic: Where is the equation v = h/(m*wavelength) derived from?
Replies: 1
Views: 503

Re: Where is the equation v = h/(m*wavelength) derived from?

p=mv and lambda=h/p. The conversion from the work function and Avogadro's number is important, so it should be committed to memory.
by Chem_Mod
Thu Aug 25, 2011 10:21 am
Forum: DeBroglie Equation
Topic: Where is the equation v = h/(m*wavelength) derived from?
Replies: 1
Views: 503

Where is the equation v = h/(m*wavelength) derived from?

Question: Where is the equation v = h/(m*wavelength) derived from? Also, in the same question, are we supposed to know how to convert the work function to energy per particle and the constant 6.022 x 10^23?
by Chem_Mod
Thu Aug 25, 2011 10:20 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: When to use certain equations?
Replies: 5
Views: 1086

Re: hv=Eupper-Elower or V=R((1/n1^2)-(1/n2^2))

Answer: One result is negative of the other. What value you use for n1 or n2 depends on the question.
by Chem_Mod
Thu Aug 25, 2011 10:20 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: When to use certain equations?
Replies: 5
Views: 1086

When to use certain equations?

Question: When calculating wavelength or frequency emitted when an electron goes from one n to another n, can I use the hv = E upper-E lower formula? In some of the problems I have been using the Rydberg formula, v=R((1/n1^2)-(1/n2^2)). Is there a right or wrong formula to use for such problems? Or...
by Chem_Mod
Thu Aug 25, 2011 10:17 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Why multiply the Rydberg Constant by Plank's constant?
Replies: 1
Views: 329

Re: Why multiply the Rydberg Constant by Plank's constant?

Answer: Wavelength is the product of h and frequency, right? The frequency is obtained from the Rydberg's formula, correct? So the two constants R and h appears.
by Chem_Mod
Thu Aug 25, 2011 10:16 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Why multiply the Rydberg Constant by Plank's constant?
Replies: 1
Views: 329

Why multiply the Rydberg Constant by Plank's constant?

Question: Why is it that you multiply the Rydberg Constant by Plank's constant?
by Chem_Mod
Thu Aug 25, 2011 10:16 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: How can the following equation be used? E(n)=(-hR)/n^2
Replies: 1
Views: 239

How can the following equation be used? E(n)=(-hR)/n^2

Question: How can the following equation be used? E(n)=(-hR)/n^2
by Chem_Mod
Thu Aug 25, 2011 10:15 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency to explain the origin of line in spectrums
Replies: 1
Views: 303

Re: use the Bohr Frequency to explain the origin of line in

Answer: The Bohr Frequency corresponds to the energy difference between two levels (see text p 15). This energy difference is the energy of the photon (or frequency or wavelength) that is given off and shows up as a line when doing a spectral analysis.
by Chem_Mod
Thu Aug 25, 2011 10:05 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency to explain the origin of line in spectrums
Replies: 1
Views: 303

Bohr Frequency to explain the origin of line in spectrums

Question: How would we use the Bohr Frequency Condition to explain the ORIGIN of lines in spectrums?
by Chem_Mod
Thu Aug 25, 2011 10:04 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: In Rydberg's formula,which energy level corresponds to n1&n2
Replies: 1
Views: 359

In Rydberg's formula,which energy level corresponds to n1&n2

Question: In Rydberg's formula v=R([1/(n1^2)]-[1/(n2^2)]), which energy level corresponds to n1 and n2? For example, does the initial energy level correspond to n1 and the terminal energy level correspond to n2? Or does the lower energy level - whether it is the initial or the terminal energy level...
by Chem_Mod
Thu Aug 25, 2011 9:59 am
Forum: Photoelectric Effect
Topic: How do we use the work function to find energy?
Replies: 1
Views: 330

Re: How do we use the work function to find energy?

Answer: The work function is determined from the kinetic energy (Ek) of the ejected photon and the energy of the light (hv) applied to the system. Ek=hv-(work function) We can rearrange this to: work function=hv-Ek. Determine the frequency, multiply it by Plank's constant to determine the energy of...
by Chem_Mod
Thu Aug 25, 2011 9:58 am
Forum: Photoelectric Effect
Topic: How do we use the work function to find energy?
Replies: 1
Views: 330

How do we use the work function to find energy?

Question: How do we use the work function to find energy?
by Chem_Mod
Thu Aug 25, 2011 9:58 am
Forum: Photoelectric Effect
Topic: What is the difference between the work function E=hv(nu)?
Replies: 1
Views: 273

Re: What is the difference between the work function E=hv(n

Answer: When the kinetic energy equals zero, they are equivalent.
by Chem_Mod
Thu Aug 25, 2011 9:58 am
Forum: Photoelectric Effect
Topic: What is the difference between the work function E=hv(nu)?
Replies: 1
Views: 273

What is the difference between the work function E=hv(nu)?

Question: What is the difference between and clarify the work function and E=hv? Does that equal the work function?
by Chem_Mod
Thu Aug 25, 2011 9:57 am
Forum: Photoelectric Effect
Topic: work function, why do we divide by Avogadro's number?
Replies: 1
Views: 345

Re: work function, why do we divide by Avogadro's number?

Answer: The work function is kJ/mol, so Avogadro's number is needed to convert moles to particles.
by Chem_Mod
Thu Aug 25, 2011 9:57 am
Forum: Photoelectric Effect
Topic: work function, why do we divide by Avogadro's number?
Replies: 1
Views: 345

work function, why do we divide by Avogadro's number?

Question: For problems using the work function, why do we divide by Avogadro's number?
by Chem_Mod
Thu Aug 25, 2011 9:56 am
Forum: Photoelectric Effect
Topic: E=hv-phi application
Replies: 1
Views: 5176

Re: E=hv-phi application

Answer: The main equation is that E(photon)=Phi+KE, where phi is the work function which is the minimum energy required to remove an electron and KE is the kinetic energy of an electron. Basically the equation is using conservation of energy. The energy given by the photon is used to remove an elec...
by Chem_Mod
Thu Aug 25, 2011 9:56 am
Forum: Photoelectric Effect
Topic: E=hv-phi application
Replies: 1
Views: 5176

E=hv-phi application

Question: The kinetic energy equation E=hv-(work function) can be written E=hv(photon)-hv(ejected). Why is it that if a problem states "Radiation of X Hz is required to eject an electron...," you plug X into the ejected half, whereas if it states "Radiation of X Hz strikes Cs and eje...
by Chem_Mod
Thu Aug 25, 2011 9:55 am
Forum: Photoelectric Effect
Topic: Energy level and Photons
Replies: 1
Views: 376

Re: question on energy level and photon match

Answer: In the first case of excitation of H atom, the energy of the incoming photon is smaller than the ionization energy of H atom. The photon can only excite the electron in H atom from lower energy state to higher energy state. Thus H atoms can only absorb photons with fixed energy. But if the ...
by Chem_Mod
Thu Aug 25, 2011 9:55 am
Forum: Photoelectric Effect
Topic: Energy level and Photons
Replies: 1
Views: 376

Energy level and Photons

Question: How does the energy difference between two energy level and the energy of the incoming photon match in order for the electron in the hydrogen atom to absorb and be excited to the next energy level? If the energy of the photon was greater than (but not great enough to excite the electron i...
by Chem_Mod
Thu Aug 25, 2011 9:51 am
Forum: *Black Body Radiation
Topic: What is "black body radiation?"
Replies: 8
Views: 1098

Re: What is "black body radiation?"

Answer: "Black body radiation" refers to the radiation that originates from the thermal energy of the body that is heated.
by Chem_Mod
Thu Aug 25, 2011 9:51 am
Forum: *Black Body Radiation
Topic: What is "black body radiation?"
Replies: 8
Views: 1098

What is "black body radiation?"

Question: What is "black body radiation"?
by Chem_Mod
Thu Aug 25, 2011 9:50 am
Forum: Einstein Equation
Topic: steps in finding the max wavelength that can break a bond?
Replies: 1
Views: 1219

Re: steps in finding the max wavelength that can break a bon

Answer: First, figure out how much energy is in a single C-C bond because one photon will interact with one bond. To do this, take the energy per mole and divide it by Avogadro's number since there are that many C-C bonds in one mole. From there, set this energy to find a wavelength using the expre...
by Chem_Mod
Thu Aug 25, 2011 9:50 am
Forum: Einstein Equation
Topic: steps in finding the max wavelength that can break a bond?
Replies: 1
Views: 1219

steps in finding the max wavelength that can break a bond?

Question: What are the steps in finding the maximum wavelength needed to break a bond (a C-C bond for example)?
by Chem_Mod
Thu Aug 25, 2011 9:49 am
Forum: Properties of Electrons
Topic: Nuclear charge and electron energies
Replies: 1
Views: 227

Re: Nuclear charge and electrons

Answer: If the electrons are strongly attracted, then the tendency for them to escape deceases. This means that the system becomes more stable and the more stable the system is the lower is its energy. Remember that nature favors stability and low energy.
by Chem_Mod
Thu Aug 25, 2011 9:45 am
Forum: Properties of Electrons
Topic: Nuclear charge and electron energies
Replies: 1
Views: 227

Nuclear charge and electron energies

Question: The greater charge of a nucleus in a many-electron atom, the stronger it attracts the electrons and therefore lowers their energy. Why would an increase in nuclear charge result in lower energy?
by Chem_Mod
Thu Aug 25, 2011 9:44 am
Forum: Properties of Electrons
Topic: What is the formal definition of the "Quantized Property"?
Replies: 1
Views: 1697

Re: What is the formal definition of the "Quantized Property

Answer: Property that has only certain discrete values, and values in between discrete values are not possible.
by Chem_Mod
Thu Aug 25, 2011 9:44 am
Forum: Properties of Electrons
Topic: What is the formal definition of the "Quantized Property"?
Replies: 1
Views: 1697

What is the formal definition of the "Quantized Property"?

Question: What is the formal definition of the "Quantized Property"?
by Chem_Mod
Thu Aug 25, 2011 9:44 am
Forum: Properties of Electrons
Topic: excited state from n=1 to n=3, do they come back down?
Replies: 1
Views: 302

Re: excited state from n=1 to n=3, do they come back down?

Answer: Upon relaxation, both cases are possible for the electron.

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