CHEMISTRY COMMUNITY

Sabrina Ryu 3L

The radical goes on the element that would have the formal charge closest to zero when the electron is added!

Sabrina Ryu 3L

I couldn't find other modules, but the chemistry in person review sessions are really helpful, especially the step-up sessions! They give you worksheets with practice problems that aren't in the book, and the TA teaches everything in detail :).

Sabrina Ryu 3L

I think charge is more important! However, when the elements are in very close proximity it is difficult to discern which has a greater effect, as the one with larger size and smaller charge will have similar polarizing power as the one with smaller size and larger charge.

Sabrina Ryu 3L

Which of the definitions of acids and bases (Bronsted, Arrhenious, or Lewis) will we be most commonly using within this class?

Sabrina Ryu 3L

Do we just have to memorize all of the common ligand names? Or will it be provided to us?

Sabrina Ryu 3L

Intermolecular forces depend on the polarity of the molecules! Dipole-dipole forces are intermolecular forces between polar molecules, while induced-dipole-induced-dipole forces are between nonpolar molecules.

Sabrina Ryu 3L

I think you should have awareness of sigma and pi bonds and be able to label these bonds whether it be N2sp3--H1s or otherwise.

Sabrina Ryu 3L

How exactly are sigma and pi bonds different? And could someone explain the different configurations of the bonding?

Sabrina Ryu 3L

Molecular shape determination can be reasoned out by first drawing the Lewis structure and then considering the repulsion of valence electrons and lone pairs. The names of molecular shapes do have to be memorized though.

Sabrina Ryu 3L

An element has too many bonds when the formal charge is unreasonably high. It should be relatively close to zero.

Sabrina Ryu 3L

Trigonal planar is flat while trigonal pyramidal is bent! This is because a molecule with trigonal pyramidal shape has a lone pair that repels the other three atoms bonded to the central atom. Trigonal planar molecules have a bond angle of 120 degrees because 360/3 = 120. However, trigonal pyramidal...

Sabrina Ryu 3L

Formal charge is important in determining the Lewis Structure, which then allows us to determine the VSEPR model and the molecular shape!

Sabrina Ryu 3L

Lone pairs make the bond strength in a single molecule weaker as well, because the lone pairs repel each other!

Sabrina Ryu 3L

Hi, I noticed that there is a test scheduled for Thanksgiving week during discussion, but there is no class during those days. Is the syllabus right? Am I missing something

Sabrina Ryu 3L

I do not believe so! As number of bonds increases, bond length decreases due to a stronger attraction.

Sabrina Ryu 3L

It is better to remove from the 4s orbital because it is the outermost shell. 3d is of higher energy, but 4s is still the outermost, or valence, shell.

Sabrina Ryu 3L

Theoretically you could form 9 bonds, but I do not know how likely it would be, especially because atoms in molecules like to maintain a formal charge closest to zero.

Sabrina Ryu 3L

The exceptions to the building up principle have to do with the d block. For elements that would have "_d4 _s2" become "_d5 _s2" according to whatever period it is in. This is because five electrons, one in each sub shell for d orbital is more stable and has lower energy than 2 e...

Sabrina Ryu 3L

Hi, 1.66x106^-17J is the work function! So it is following the equation (1/2)mv^2 = hv - (work function). It is just rearranged so you can find the energy (hv).

Sabrina Ryu 3L

Hi! I wanted to know which of the review/Q&A sessions helped the most? Was it office hours? step up sessions? I wanted to go to multiple but it was overwhelming to even decide which to go to.

Sabrina Ryu 3L

I think you mean nitrogen and oxygen? That is one of the exceptions to the ionization energies increasing from left to right, because oxygen is in group 16 and nitrogen is in group 15. This is because the electron configuration of nitrogen is more stable, because all of the p orbitals only have one ...

Sabrina Ryu 3L

Nope! You can choose any seven questions from the section for homework.

Sabrina Ryu 3L

Posting three times during a day is the same amount of points as posting throughout the week! You just need to have three by the end of the week.

Sabrina Ryu 3L

The photoelectric effect supports the idea that electromagnetic radiation has particle-like qualities, because a certain packet of energy (photons) is necessary to eject electrons of an atom, meaning EM radiation is quantized. If electrons were only wavelike, it would be a continuous spectrum.

Sabrina Ryu 3L

The differing energy levels depends on which series of the electromagnetic spectrum you are using! When the question asks about the visible light spectrum, you are using the Balmer series, where n1 = 2. Otherwise, when asked about the ultraviolet part of the spectrum, you are using the Lyman series,...

Sabrina Ryu 3L

Light does act as both a wave and a particle! On Monday's lecture we focused on the particle aspect while talking about the photoelectric effect, black bodies, and atomic spectra. However, if you read the book there are more details about the wave aspect of light, including diffraction and the Schro...

Sabrina Ryu 3L

I also heard that you should use the full number given to you on the periodic table. During lecture, Lavelle also said that you shouldn't round until the very end, so you should use the full values that you calculate whether it be grams, moles, etc.

Sabrina Ryu 3L

I believe that molar ratios and stoichiometric ratios are synonymous. They describe the ratio between the number of moles of compounds in a chemical equation.

Sabrina Ryu 3L

In this problem, "M" is an unknown metal, but we know that M(OH)2 has a molar mass of 74.10 g/mol. Thus, we can subtract the molar mass of the OH portions of the molecule (17.01*2 g/mol) to get 40.08 g/mol of metal "M." We know that "M" has a charge of +2, because it bo...

Sabrina Ryu 3L

In order to find how many molecules remain after 90 doublings, you first have to calculate how many molecules are in the 10mL of solution: .010 mL x (0.10 mol/L) x (6.022*10^23 molecules/1mol) = 6.0 x 10^20 molecules. Then, you could set up an exponential formula: 6.0 x 10^22 molecules x (0.5^n)= # ...

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Radical Placement

Re: Modules

Re: Polarizing power precedence

Bronsted, Arrhenious, or Lewis?

Naming Coordination Compounds

Re: Identifying intermolecular forces

Re: Identifying types of bonds and hybridization in Lewis Structures

sigma and pi bonds

Re: Memorization

Re: Maximum amount of bonds

Re: Trigonal Shapes

Re: Formal Charge

Re: Lone Pairs and Bond Strengths

Test during Thanksgiving Week?

Re: Special Bond Length Rules

Re: Electron removal from orbitals question

Re: Max # of bonds

Re: Exceptions for the Building-Up principle

Re: b15

Re: Advice from a Medical Student [ENDORSED]

Re: Ionization Energy

Re: Homework

Re: Points

Re: electromagnetic radiation

Re: Rydberg Equation n

Re: Light acts as a wave or not?

Re: Periodic Table

Re: Mole Ratios & Stoichiometric Relations

Re: MOLAR MASS

Re: Question G25 in 6th edition [ENDORSED]