Search found 35 matches

by Noah Canio 3C
Mon Nov 11, 2019 12:50 am
Forum: Lewis Structures
Topic: Lewis Dot Structures
Replies: 6
Views: 21

Re: Lewis Dot Structures

Compounds with an odd number of electrons are defined as radicals and are supposed to be very reactive in nature. I've honestly been trying to figure out which atom is supposed to get the extra electron for days leading up to the midterm exam. I found that either you comply to the necessary formal c...
by Noah Canio 3C
Mon Nov 11, 2019 12:47 am
Forum: Lewis Structures
Topic: Formal Charges
Replies: 15
Views: 42

Re: Formal Charges

In the case that it's impossible for the compound to not have nonzero values for its formal charges, then the negative charges must be delegated to the compound's most electronegative atoms while the least ones will typically have positive formal charges. For compounds with neutral charges, these fo...
by Noah Canio 3C
Mon Nov 11, 2019 12:43 am
Forum: Bond Lengths & Energies
Topic: Test 2 Topics
Replies: 17
Views: 86

Re: Test 2 Topics

It should most likely include concepts pertaining to molecular shape and structure as well as those slides regarding dipole-dipole interactions, hydrogen bonds, covalent bonds, and ionic bonds that were covered by Dr. Lavelle on the last slide on the Friday before the midterm exam.
by Noah Canio 3C
Mon Nov 11, 2019 12:41 am
Forum: Dipole Moments
Topic: Dipole Moment
Replies: 6
Views: 14

Re: Dipole Moment

A dipole moment is essentially just the difference in charges between different atoms in a compound. This is typically found by comparing each atom's electronegativity to each other.
by Noah Canio 3C
Mon Nov 11, 2019 12:39 am
Forum: Electronegativity
Topic: Ionization energy of O vs N
Replies: 6
Views: 20

Re: Ionization energy of O vs N

This is based on the electron configuration of both oxygen and nitrogen. Oxygen has two unpaired electrons in its 2p orbitals while Nitrogen has three unpaired electrons. Based on my experience with one of the UA's, the symmetry of the electrons in nitrogen indicated by having a half complete valenc...
by Noah Canio 3C
Mon Nov 11, 2019 12:37 am
Forum: Electronegativity
Topic: Atom size
Replies: 10
Views: 28

Re: Atom size

Typically electronegativity has the "opposite" trend in comparison to that of atomic radius. This is because the trend in the periodic table for electronegativity is increasing from left to right and bottom to top. In contrast, atomic radius increases from right to left and from top to bot...
by Noah Canio 3C
Mon Nov 11, 2019 12:33 am
Forum: Electronegativity
Topic: Electronegativity between Oxygen and nitrogen
Replies: 2
Views: 6

Re: Electronegativity between Oxygen and nitrogen

As mentioned above, it's because of oxygen's number of protons. If you want a reason based on periodic trends, electronegativity increases from left to right and from bottom to top. Oxygen is on the right of nitrogen.
by Noah Canio 3C
Mon Nov 11, 2019 12:31 am
Forum: Lewis Structures
Topic: Polar and Non polar covalent bonds in lewis structures
Replies: 2
Views: 5

Re: Polar and Non polar covalent bonds in lewis structures

You don't necessarily have to define them as such, but understanding that some compounds are either polar or non-polar would help you understand the composition of a given compound. If they're polar, then they're represented with "dipole moments," as there's going to be a portion of the co...
by Noah Canio 3C
Mon Nov 11, 2019 12:28 am
Forum: Properties of Electrons
Topic: Electron affinity
Replies: 3
Views: 29

Re: Electron affinity

Electron affinity follows nearly the same trend in the periodic table as electronegativity. However, by definition, these traits differ. Electron affinity refers to the amount of energy that an atom releases when it takes an electron. In contrast, electronegativity refers to the general ability for ...
by Noah Canio 3C
Mon Nov 11, 2019 12:25 am
Forum: Properties of Light
Topic: How to find the longest wavelength?
Replies: 6
Views: 18

Re: How to find the longest wavelength?

The longest wavelength, as everyone mentioned, comes from the work function. Using the value of energy from the work function, solve for wavelength using E = h(c)/(wavelength).
by Noah Canio 3C
Sun Nov 03, 2019 3:36 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 5
Views: 27

Re: Formal Charge

Like everyone above mentioned, formal charge should be calculated always when drawing Lewis structures. However, when drawing the "best" structure or the one with the lowest energy, it's important to note that you should calculate formal charge only after: 1.) Making sure your structure co...
by Noah Canio 3C
Sun Nov 03, 2019 3:14 pm
Forum: Trends in The Periodic Table
Topic: Electronegativity vs. Electron Affinity
Replies: 3
Views: 17

Re: Electronegativity vs. Electron Affinity

Electronegativity refers to how well an atom can attract an electron to itself when that atom is within a molecule while electron affinity, as mentioned above, refers to how much energy is released when an atom takes in an electron (the more simple and easier to understand definition would be the at...
by Noah Canio 3C
Sun Nov 03, 2019 1:55 pm
Forum: Trends in The Periodic Table
Topic: Exceptions
Replies: 4
Views: 17

Re: Exceptions

Nitrogen has a higher ionization energy than oxygen. If you look at the electron configuration of both, Nitrogen has a half-filled 2p orbital while oxygen has two unpaired electrons in the 2p orbital. Due to the symmetry of the electrons, more energy is required to remove an electron from a nitrogen...
by Noah Canio 3C
Sat Nov 02, 2019 11:38 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1.E.1
Replies: 2
Views: 24

Re: 1.E.1

If I remember correctly from the UA review session from Friday, one of the UA's stated that the subshells, values of l, for the hydrogen ion are degenerate. This means that they will have the same energy (all e- in s,p,d, etc. because there's only 1 electron). Besides that, all other atoms should ha...
by Noah Canio 3C
Sat Nov 02, 2019 11:24 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Filling of Orbitals
Replies: 2
Views: 13

Re: Filling of Orbitals

Since we're on the topic, the commenter above has got the correct explanation. It's important to note that this scenario, that is, having the d-orbital filled, takes place for all elements within chromium's column and copper's column (silver is underneath copper in the periodic table). In the case o...
by Noah Canio 3C
Sun Oct 27, 2019 4:23 pm
Forum: Properties of Electrons
Topic: Subshell Exceptions
Replies: 6
Views: 40

Re: Subshell Exceptions

In one of the UA sessions that I went to today, the UA told us to write Cr as [Ar]3d 5 4s 1 instead of [Ar]4s 1 3d 5 . I do not know why he said that but can someone better explain this to me? As the 3d orbital gains more electrons, it ends up having less energy than the 4s orbital. Since we're sup...
by Noah Canio 3C
Sun Oct 27, 2019 4:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Block Confusion
Replies: 4
Views: 37

Re: Block Confusion

In short, 3d has more energy than 4s simply because it stole one of the electrons of 4s. This is because 3d has an incomplete set of electrons in its orbitals but the 4s orbital is complete and because 3d wants to be complete too, it takes an electron from 4s and gives its last orbital an electron....
by Noah Canio 3C
Sun Oct 27, 2019 3:48 pm
Forum: *Shrodinger Equation
Topic: Wave functions
Replies: 9
Views: 56

Re: Wave functions

Wave functions represent the mathematical likelihoods of finding an electron in an atom. The orbital shapes, like the s or p, can be described as "solutions" to those mathematical functions (wave functions).
by Noah Canio 3C
Sun Oct 27, 2019 3:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Number
Replies: 3
Views: 28

Re: Quantum Number

As Ariana mentioned, the spin projection quantum number can only be either +1/2 or -1/2 for any electron in a particular orbital. In an electron configuration, +1/2 is indicated by an arrow pointing upwards while -1/2 is indicated by an arrow pointing downwards.
by Noah Canio 3C
Sun Oct 27, 2019 3:30 pm
Forum: Properties of Light
Topic: 1.31
Replies: 4
Views: 36

Re: 1.31

Recall this equation:



You're supposed to determine which laser to use. Take the appropriate laser's wavelength and use u = C/ lamda to solve for the energy of the photon.

Subtract the energy by the work function to find the energy emitted by the electron.
by Noah Canio 3C
Sun Oct 20, 2019 2:44 pm
Forum: Photoelectric Effect
Topic: if KE is 0 how can the electron be ejected?
Replies: 4
Views: 45

Re: if KE is 0 how can the electron be ejected?

If I remember correctly, Dr. Lavelle explained that the detector used to measure the kinetic energy of the ejected electron has a slight positive charge. This means that even if the electron is hit with an energy equal to the threshold needed (the work function), the electron will move slightly away...
by Noah Canio 3C
Sun Oct 20, 2019 2:39 pm
Forum: DeBroglie Equation
Topic: Wavelike properties of protons
Replies: 2
Views: 18

Re: Wavelike properties of protons

I agree with the post above, typically really small objects with momentum have perceivable wave-like properties. One exception to this is a photon. Despite it not having a mass, it can still have momentum. The reason as to why this is goes beyond the scope of this class, but because a photon can hav...
by Noah Canio 3C
Sun Oct 20, 2019 2:04 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Indeterminacy
Replies: 1
Views: 13

Re: Indeterminacy

You're on the right track, the value you'd use for uncertainty will need to utilize the +/- value.

Example: 5m/s with +/- 1.

5+1 = 6
5-1 = 4

6-4=2.

You'd use the value of 2 in the uncertainty equation for velocity.
by Noah Canio 3C
Sun Oct 20, 2019 2:00 pm
Forum: Properties of Light
Topic: Unit for Wavelength
Replies: 34
Views: 120

Re: Unit for Wavelength

As mentioned by people in this thread, it looks like wavelength is going to measured in nm (nanometers). If you remember the equation: speed of light = frequency*wavelength You should notice that the speed of light has the units (meters/second). Since frequency is cycles per second or (per second), ...
by Noah Canio 3C
Mon Oct 14, 2019 8:35 pm
Forum: Properties of Electrons
Topic: Question from Heisenberg's Uncertainty Principle post test
Replies: 2
Views: 48

Re: Question from Heisenberg's Uncertainty Principle post test

1% of 0.05 nm is 0.01 x 0.05nm= 5e-4m This guy is essentially performing the first step of the problem. The uncertainty in position is equal to 1% of the radius of the hydrogen atom. Next, you'd need to get this value in meters. Finally, all you're doing is solving for velocity by dividing (h/4π) b...
by Noah Canio 3C
Sun Oct 13, 2019 2:31 pm
Forum: DeBroglie Equation
Topic: Problem 1B.7
Replies: 3
Views: 26

Re: Problem 1B.7

The units makes this question pretty tricky. Just remember that we're dealing with atoms of sodium. And in part 1, you solved for the energy emitted by a single sodium electron. So, in order to answer this question, we need to figure out how many atoms of sodium are present within 5.00mg of sodium. ...
by Noah Canio 3C
Sun Oct 13, 2019 2:21 pm
Forum: Properties of Light
Topic: 1A.3
Replies: 3
Views: 27

Re: 1A.3

I'm also confused about the relationship between the frequency of electromagnetic radiation and the extent of change in the electrical field. I second DHavo_3H's post. The extent of change in an electrical field at a given point has a positive correlation to the frequency of electromagnetic radiati...
by Noah Canio 3C
Sun Oct 13, 2019 12:44 am
Forum: Photoelectric Effect
Topic: How much energy to remove one electron?
Replies: 8
Views: 85

Re: How much energy to remove one electron?

Jk what i did was on the right track. Since the work function is the same as the threshold, I converted 150.6 kJ/mol to 1.506x10^5 J/mol. However, since the units are J/mol, I need to divide by Avogadro's constant, (6.022x10^23 electrons/mol) which would cancel out the moles and leave me with just ...
by Noah Canio 3C
Sun Oct 13, 2019 12:20 am
Forum: Photoelectric Effect
Topic: threshold energy
Replies: 6
Views: 18

Re: threshold energy

In the case of the photoelectric effect, the energy of a photon of light must be greater than or equal to the threshold energy required for an electron to be shot out or removed. If you remember the experiment, scientists were trying to figure out how intense light must be in order to remove electro...
by Noah Canio 3C
Sun Oct 13, 2019 12:14 am
Forum: Einstein Equation
Topic: Numbers to memorize [ENDORSED]
Replies: 37
Views: 953

Re: Numbers to memorize [ENDORSED]

It would be convenient to memorize these numbers, but he does indeed offer a cheat sheet of equations to utilize for every test that we take. The particular cheat sheet is actually on his website: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/constants_equations.pdf (If I remembe...
by Noah Canio 3C
Thu Oct 03, 2019 9:13 pm
Forum: Significant Figures
Topic: Sig figs in intermediate steps??
Replies: 5
Views: 26

Re: Sig figs in intermediate steps??

As mentioned before, decimal precision in immediate steps is the way to go. Just keep as many decimal points in your calculator as possible as you go through any problem and then your final answer should abide to the amount of sig figs you need. (Note: when showing work for intermediate steps, decim...
by Noah Canio 3C
Thu Oct 03, 2019 9:08 pm
Forum: SI Units, Unit Conversions
Topic: Kelvin, Celsius, & Fahrenheit Conversions
Replies: 3
Views: 28

Re: Kelvin, Celsius, & Fahrenheit Conversions

Kelvin (K) = 273.15 + ºC

Celsius (ºC) = K - 273.15
OR
(ºF)(5/9) - 32

Fahrenheit (ºF) = (ºC)(1.8) + 32
by Noah Canio 3C
Thu Oct 03, 2019 4:53 pm
Forum: SI Units, Unit Conversions
Topic: E.1 7th edition
Replies: 4
Views: 33

Re: E.1 7th edition

This problem appears to be asking for the length of an entire line of Ag atoms stringed together. We're given the amount of atoms in moles (which again is a unit of measuring many atoms). If we want the total number of atoms in actual atoms and not moles, then we'd multiply 1 mol of Ag by avogadro's...
by Noah Canio 3C
Thu Oct 03, 2019 4:33 pm
Forum: SI Units, Unit Conversions
Topic: Sig Figs: follow the book or follow Sig Fig rules?
Replies: 3
Views: 44

Re: Sig Figs: follow the book or follow Sig Fig rules?

That's strange, can you state some examples of problems that display this? I'm looking around the solutions manual myself and it seems like sig figs are correct for the most part. Regardless of whether or not the solutions manual doesn't abide to sig figs, I'd say go for displaying your answers in s...
by Noah Canio 3C
Thu Oct 03, 2019 2:49 pm
Forum: Properties of Light
Topic: Quantum homework
Replies: 4
Views: 50

Re: Quantum homework

I just wanted to clarify: because the chemistry review section was "recently learned," we can theoretically submit five questions from that section for credit as opposed to submitting questions from the quantum world section?

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