## Search found 30 matches

Thu Jun 07, 2018 7:01 am
Forum: Ionic & Covalent Bonds
Topic: Help on 3.53
Replies: 2
Views: 213

### Re: Help on 3.53

When you're trying to calculate the formal charge, you want to find the number of Valence electrons the atom owns, and the number of "things" that it has surrounding the atom. By "things" I mean the number of bonds and non bonded valence electrons added up together. Thus the equa...
Thu Jun 07, 2018 6:58 am
Forum: Naming
Topic: Oxidation
Replies: 3
Views: 337

### Re: Oxidation

This website is a good reference on how to find the oxidation number.
https://socratic.org/questions/how-do-y ... a-compound
Thu Jun 07, 2018 6:57 am
Forum: Ionic & Covalent Bonds
Topic: Help on 3.49
Replies: 2
Views: 221

### Re: Help on 3.49

The formal charge on the carbons is both 01
There is a triple bond between C and C, with one lone pair on each. Carbon's Valence is 4, so 4-5 (the number of bonds&valence)=-1
Fri Jun 01, 2018 1:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 7
Views: 392

### Re: Bond Angles

I'm pretty sure we're not going to be expected to know the exceptions from repulsion (was told this in discussion), but we do need to know the main bond angles of each shape.
Wed May 30, 2018 2:31 pm
Forum: Hybridization
Topic: Hybrid
Replies: 1
Views: 123

### Re: Hybrid

Yes, regions of electron density= # of hybrid orbitals
Tue May 29, 2018 9:10 pm
Forum: Resonance Structures
Topic: How to determine resonance
Replies: 2
Views: 260

### Re: How to determine resonance

You can essentially move the bonds from top left right, etc.
Tue May 29, 2018 9:08 pm
Forum: Lewis Structures
Topic: Lewis Structures and Coordinate Covalent Bonds
Replies: 1
Views: 199

### Re: Lewis Structures and Coordinate Covalent Bonds

It can be, but since professor lavelle hasn't brought it up I wouldn't worry about it.

^examples
(weird intro music, stick with it)
Tue May 29, 2018 9:04 pm
Forum: Lewis Structures
Topic: Electrons in Valence Shell
Replies: 4
Views: 394

### Re: Electrons in Valence Shell

I think it really just depends on the atom you're looking at. For example Sulfur has an expanded octet of twelve electrons.
This website is pretty helpful for reference.

https://opencurriculum.org/9814/what-is ... nce-shell/
Tue May 29, 2018 9:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Cancelling out dipole moments
Replies: 3
Views: 456

### Cancelling out dipole moments

When drawing a VSEPR structure and determining if the molecule is polar or nonpolar, how do you know when dipole moments cancel?
Thu May 24, 2018 6:49 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Ammonia shape [ENDORSED]
Replies: 2
Views: 227

### Ammonia shape[ENDORSED]

I know we talked about this in lecture, but I am still slightly confused on why NH3 is trigonal pyramidal?
Tue May 22, 2018 10:00 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 367

### Re: Bond Angles

I don't know the in-depth answer, but yes.
This website does a good job explaining it.

https://socratic.org/questions/how-does-bonding-affect-molecular-geometry
Tue May 22, 2018 9:59 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dispersion/Induced Dipole-Induced Dipole/London/Van Der Waals
Replies: 1
Views: 292

### Re: Dispersion/Induced Dipole-Induced Dipole/London/Van Der Waals

That is the equation for the interaction potential energy - it is the energy it takes to pull the bonds (induced dipole-induced dipole, dipoles, hydrogen) apart. When two molecules come close together, the two molecules have both attractive (dipoles) and repulsive forces (electron clouds of two mole...
Sun May 20, 2018 9:30 pm
Forum: Lewis Structures
Topic: chapter 3 hw #57 question
Replies: 5
Views: 299

### Re: chapter 3 hw #57 question

Sun May 20, 2018 9:19 pm
Forum: Dipole Moments
Topic: Dipole going from positive to negative
Replies: 1
Views: 106

### Re: Dipole going from positive to negative

The direction of dipole moment is from positive poles to negative poles because the electrons in covalent bonds are not always equally shared. When there is an increasing difference in electronegativity, it results in an increasing difference in the charge of the two atoms, increasing the ionic char...
Sun May 20, 2018 8:32 pm
Forum: Ionic & Covalent Bonds
Topic: Test 3 [ENDORSED]
Replies: 7
Views: 519

### Re: Test 3[ENDORSED]

We won't be expected to know the names of ionic compounds.
Sun May 20, 2018 8:30 pm
Forum: Ionic & Covalent Bonds
Topic: delta positive and delta negative
Replies: 2
Views: 321

### Re: delta positive and delta negative

A negative dipole should be on the side that is more electronegative, and takes in electrons. It will be able to pull other electrons to it and become more negative. Thus, the positive dipole is the one that is less electronegative, giving off electrons and becoming more positive.
Fri May 18, 2018 8:39 pm
Forum: Dipole Moments
Topic: Positive and Negative Dipole [ENDORSED]
Replies: 2
Views: 275

### Positive and Negative Dipole[ENDORSED]

I'm a bit confused on how to determine whether or not a dipole is positive or negative in an ionic or covalent bond.
Thu May 17, 2018 7:06 am
Forum: Ionic & Covalent Bonds
Topic: Ionic bonds
Replies: 6
Views: 439

### Re: Ionic bonds

I'm pretty sure we haven't entirely covered this yet in class, but in drawing ionic bonds you have to show the transfer of electrons from one atom to another. Check out this diagram and website for an example of the ionic bond between Na+ and Cl- https://chem.libretexts.org/@api/deki/files/1778/ioni...
Thu May 17, 2018 6:52 am
Forum: Ionic & Covalent Bonds
Topic: How to tell which elements will be most likely to form a covalent bond
Replies: 8
Views: 494

### How to tell which elements will be most likely to form a covalent bond

If you're given a list of elements such as
K and Cl
H and O
Al and Mg
K and Na
how do you tell which elements will most likely form a covalent bond?
Thu May 17, 2018 6:42 am
Forum: Bond Lengths & Energies
Topic: exceptions
Replies: 1
Views: 159

### Re: exceptions

Bonds between like atoms usually become weaker as we go down a column because as two bonded atoms become larger, the distance between them that is occupied by bonding electrons becomes proportionally smaller. Exceptions are single bonds between the period 2 atoms of groups 15, 16, and 17 (i.e., N, O...
Thu May 17, 2018 6:34 am
Forum: Lewis Structures
Topic: HW 3.41
Replies: 2
Views: 149

### Re: HW 3.41

That is correct, it would just be a resonance structure of ch3oh
Sat May 12, 2018 3:13 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charges and full valence shells
Replies: 3
Views: 290

### Formal charges and full valence shells

What is the relationship between having full valence shells and formal charges? Do full valence shells always result in a formal charge of zero?
Tue May 08, 2018 7:58 pm
Forum: Trends in The Periodic Table
Topic: electron affinity [ENDORSED]
Replies: 15
Views: 826

### Re: electron affinity[ENDORSED]

The electron's affinity measures the energy given off when one mole of atoms in the gaseous state each takes in one (or more) electrons to become a mole of anions in the gaseous state, or basically the energy required to gain an electron to become an anion. That being said, the nuclear charge of an ...
Mon Apr 30, 2018 6:54 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrons occupying a subshell [ENDORSED]
Replies: 1
Views: 68

### Re: Electrons occupying a subshell[ENDORSED]

Given l (the type of subshell), you can use it to find the magentic quantum number ml=-l...0...+l. This number divides the subshell into individual orbitals (s,p,d,f) which hold the electrons; there are 2l+1 orbitals in each subshell. Thus the s subshell has only one orbital, the p subshell has thre...
Mon Apr 30, 2018 6:40 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin Number (Ms)
Replies: 3
Views: 133

### Re: Spin Number (Ms)

The spin quantum number tells us the spin of the electron and is the fourth quantum number. There can only be two electrons in an orbital (Pauli's exclusion principle) and the values for ms are +1/2 and -1/2. Since electrons spin on its axis, it has both angular momentum and orbital angular momentum...
Wed Apr 25, 2018 2:21 pm
Forum: *Shrodinger Equation
Topic: Quantum numbers & orbitals
Replies: 1
Views: 179

### Quantum numbers & orbitals

Professor Lavelle said that during lecture 2s and 2p are the same in a Hydrogen atom. Why is that?
Thu Apr 19, 2018 12:42 am
Forum: Properties of Electrons
Topic: Practice Problem
Replies: 1
Views: 186

### Re: Practice Problem

Because there is zero kinetic energy given in the question, we know that the equation to use would be KE = Ep - energy needed to eject an electron (threshold). The threshold is given as 3.607 x 10-19 J and KE would be zero.
Solving algebraically for wavelength by setting Ep = $\frac{hc}{\lambda }$
Wed Apr 18, 2018 2:39 pm
Forum: DeBroglie Equation
Topic: Measurable Wavelike properties
Replies: 3
Views: 224

### Measurable Wavelike properties

In lecture, professor Lavelle went how over solving a DeBroglie equation and asked whether or not the wavelength had measurable wavelike properties. One of the answers did while the other didn't. How did he go about solving that?
Wed Apr 18, 2018 2:29 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Frequency if energy goes from n=2 to n=4
Replies: 6
Views: 269

### Re: Frequency if energy goes from n=2 to n=4

The higher the energy of a photon absorbed, the higher the energy level it jumps to. Energy of a photon can not be negative.
Wed Apr 18, 2018 2:11 pm
Forum: DeBroglie Equation
Topic: Homework 1.33 Part C
Replies: 3
Views: 214

### Homework 1.33 Part C

Part C asks "what is the wavelength of the radiation that caused photoejection of the electron?" Is that referring to the wavelength of the electron that is emitted, or is it talking about the energy that is needed to eject the electron? Could you just use the E=hc/wavelength formula or wo...