CHEMISTRY COMMUNITY

Alicia Yu 1A

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...

Alicia Yu 1A

This website is a good reference on how to find the oxidation number.
https://socratic.org/questions/how-do-y ... a-compound

Alicia Yu 1A

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

Alicia Yu 1A

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.

Alicia Yu 1A

Yes, regions of electron density= # of hybrid orbitals

Alicia Yu 1A

You can essentially move the bonds from top left right, etc.

Alicia Yu 1A

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

https://www.youtube.com/watch?v=mJppwhJvTLc
^examples
(weird intro music, stick with it)

Alicia Yu 1A

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/

Alicia Yu 1A

When drawing a VSEPR structure and determining if the molecule is polar or nonpolar, how do you know when dipole moments cancel?

Alicia Yu 1A

I know we talked about this in lecture, but I am still slightly confused on why NH3 is trigonal pyramidal?

Alicia Yu 1A

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

Alicia Yu 1A

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...

Alicia Yu 1A

You may want to reference this website, it explains it pretty well.
https://chemistry.stackexchange.com/questions/6447/why-does-clo%E2%82%84%E2%81%BB-only-have-3-double-bonds

Alicia Yu 1A

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...

Alicia Yu 1A

We won't be expected to know the names of ionic compounds.

Alicia Yu 1A

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.

Alicia Yu 1A

I'm a bit confused on how to determine whether or not a dipole is positive or negative in an ionic or covalent bond.

Alicia Yu 1A

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...

Alicia Yu 1A

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?

Alicia Yu 1A

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...

Alicia Yu 1A

That is correct, it would just be a resonance structure of ch3oh

Alicia Yu 1A

What is the relationship between having full valence shells and formal charges? Do full valence shells always result in a formal charge of zero?

Alicia Yu 1A

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 ...

Alicia Yu 1A

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...

Alicia Yu 1A

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...

Alicia Yu 1A

Professor Lavelle said that during lecture 2s and 2p are the same in a Hydrogen atom. Why is that?

Alicia Yu 1A

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 = $\frac{hc}{\lambda }$

Alicia Yu 1A

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?

Alicia Yu 1A

The higher the energy of a photon absorbed, the higher the energy level it jumps to. Energy of a photon can not be negative.

Alicia Yu 1A

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...

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Help on 3.53

Re: Oxidation

Re: Help on 3.49

Re: Bond Angles

Re: Hybrid

Re: How to determine resonance

Re: Lewis Structures and Coordinate Covalent Bonds

Re: Electrons in Valence Shell

Cancelling out dipole moments

Ammonia shape [ENDORSED]

Re: Bond Angles

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

Re: chapter 3 hw #57 question

Re: Dipole going from positive to negative

Re: Test 3 [ENDORSED]

Re: delta positive and delta negative

Positive and Negative Dipole [ENDORSED]

Re: Ionic bonds

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

Re: exceptions

Re: HW 3.41

Formal charges and full valence shells

Re: electron affinity [ENDORSED]

Re: Electrons occupying a subshell [ENDORSED]

Re: Spin Number (Ms)

Quantum numbers & orbitals

Re: Practice Problem

Measurable Wavelike properties

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

Homework 1.33 Part C