CHEMISTRY COMMUNITY

Bryan Jiang 1F

The porphyrin ligand was the tetradentate structure with four N surrounding the Fe atom.

Bryan Jiang 1F

I think it is the very fact that the lone pair pushes the four bonded atoms down that creates the pyramidal shape. Of course, there is an additional axial/vertical bonded atom pointing down too, but the most characteristic feature of AX5E would be the depressed four bonded atoms from the lone pair.

Bryan Jiang 1F

You have the right reasoning but just the wrong information. There was a figure associated with the question which explains why the answer is 3 At atoms.

Left: 9 Ga (9 x 70 g/mol = 630 g/mol)
Right: 210 g/mol x 3 At = 630 g/mol

Answer: 3 At

Bryan Jiang 1F

The exception is probably just palladium. Because exceptions to exceptions become more prominent down the periods, Dr. Lavelle wants us to focus on just up to the first row of transition metals where the exceptions are regular. This means that we are not expected to know the exceptions to exceptions...

Bryan Jiang 1F

Not only every atom, but also lone pairs. Both a bound atom and a lone pair are each referred to as an electron density region. So it is like a rule of thumb that every region of electron density should be as far from the other in determining the molecular shape, which takes up 3-dimensional space.

Bryan Jiang 1F

A chelate is a structure resembling a ring that results when a special ligand associates with a central atom, usually a cation. So, it is a complex made of two parts: 1. An atom, usually a cation, that will become the central atom once it is bound by the second part of the complex, the chelating lig...

Bryan Jiang 1F

For iodine trichloride, the VSEPR formula I got was AX3E2. The iodine is the central atom and has bonds with three chlorine. With 28 electrons to use, you should end up with two remaining lone pairs. I am do not think this shape was taught in lecture, but the shape is T-shaped.

Bryan Jiang 1F

In lecture, it seems that the original convention (arrow pointing towards the partial negative charge) was used. However, I think Dr. Lavelle made a comment that in physics, the arrow pointing toward the partial positive charge is common.

Bryan Jiang 1F

Yes, since for one of the bonds in the triple bond the oxygen provides two electrons, this makes it a coordinate covalent bond between the carbon and oxygen in CO.

Bryan Jiang 1F

So as you said, both CaO and CaS have the same polarizing cation, Ca2+. The reason that CaS would have a greater covalent character than CaO would thus be attributed to the different polarized anions. S2- will be larger than O2- by one outer shell. This makes the electron cloud of S2- be more vulner...

Bryan Jiang 1F

I think it’s also important to remember that this is just a guideline. Finding formal charges might be the best way to determine which atom should be the central atom. Consider the case for ONF (from problem 3.33). Although oxygen technically has the lowest ionization energy of the three elements, i...

Bryan Jiang 1F

I think that sulfur has a higher ionization energy because generally ionization energy increases across the periodic table. You are right in that ionization energy generally increases across a period, but only generally . For the case between phosphorus and sulfur, phosphorus would actually have th...

Bryan Jiang 1F

One would have to look at properties other than electronegativity difference to tell what kind of bond is present.

Bryan Jiang 1F

In addition to only having one electron, hydrogen also only has one orbital, the 1s orbital. So once hydrogen is sharing electrons with another atom, this one orbital that hydrogen has will be used up for this sharing. Any additional atom that wants to share electrons with this hydrogen cannot do so...

Bryan Jiang 1F

sharonvivianv wrote:They are electrons that are not used while making bonds

I don’t think that is totally true. Lone pairs also are electrons that are not used “while making bonds.” But radicals are more specific, like what Emily said above, that radicals involve a single, unpaired valence electron.

Bryan Jiang 1F

I calculated the answers to be D and A respectively. 21. ΔpΔx ≥ h/4π. Heisenberg’s Indeterminancy Equation. Δx = 2.5 x 10^-10 m. Given. Δp(2.5 x 10^-10) ≥ h/4π. Plug Δx into Heisenberg’s Indeterminancy Equation. Δp ≥ 2.1 x 10^-25 kg.m.s^-1. Answer as electron’s uncertainty in momentum. ——— Δp = mΔv....

Bryan Jiang 1F

The following is from a response from another topic:

Chem_Mod wrote:The midterm will cover everything until end of ch2.

Bryan Jiang 1F

Electron configuration should be ordered primarily by increasing order of shells, the principle quantum number n. Given this, we also know that when we start including the d-orbitals in the electron configuration, the highest shell in which the d-orbitals reside in “lags” behind the highest shell in...

Bryan Jiang 1F

Even though the same information about the electron configuration is displayed by both of those ways, one should still order the electron groupings by n-values first to denote the fact that the shells are the primary differences in energy levels. Dr. Lavelle mentions this preference for n-value orde...

Bryan Jiang 1F

When we draw out an electron diagram, we indicate the first electrons in orbitals with the up arrow first. Does this imply that all electrons prefer to spin one way (the up arrow spin, counterclockwise) when occupying an orbital by itself?

Bryan Jiang 1F

I believe that moving from n=5 to n=3 takes up more energy which makes the wavelength smaller, less frequency When electrons are dropping from higher energy levels to lower energy levels, energy is RELEASED as a photon, not taken up. Since the drop from n=5 to n=3 is larger than the drop from n=4 t...

Bryan Jiang 1F

Yes we need to know the different energy levels for the balmer (n=2) and lyman (n=1) series. I think that it is also important to know that there are only 7 different energy levels. What do you mean by what you said that there are only 7 different energy levels? I thought the number of energy level...

Bryan Jiang 1F

It felt pretty short since I practiced problems with unlimited time. I think next time I’ll try to practice under time pressure.

Bryan Jiang 1F

Yes, anything with momentum has a wavelength, including cars. The example of a car I think was used to demonstrate that literally anything with momentum has a wavelength, but the scales where finding this wavelength is more relevant is when talking about particles.

Bryan Jiang 1F

λ = h/p, then
λ = c/ν —> ν = c/λ gives you frequency.

Bryan Jiang 1F

You are correct. λ=h/p cannot apply to light because light does not have mass. As a consequence, photons also have no mass.

Bryan Jiang 1F

This is more of a question with sigfigs. Since we have not formally talked about sigfigs in lecture, I do not think the rounding matters for now. Also, be careful of the negative signs in your exponents!

Bryan Jiang 1F

It would help to know what energy levels are associated with what part of the EM spectrum. So in the problem you mentioned, recognizing a wavelength of 102.6 nm as being ultraviolet light, and knowing that ultraviolet light is associated with the n=1 energy level (Lyman series) would be really helpf...

Bryan Jiang 1F

Continuing on with what Jimmy shared, how the order relates to frequency and wavelength, think of the “rays” end of the EM spectrum (x-rays and gamma rays) as being dangerous and thus high energy. A higher frequency/shorter wavelength will correspond to higher energy. So, as you approach gamma rays,...

Bryan Jiang 1F

What spectroscopic series an energy transition belongs to depends on what energy level an electron jumps from when absorbing energy or what energy level an electron drops to when emitting energy. So for an H-atom, if an electron jumps from or drops to the n=1 energy level, these lines will be of the...

Bryan Jiang 1F

In the context of E=hv, h tells us how E and v relate to each other. We know that E and v are proportional in some way, and through experiments, scientists were able to find that E and v relate to each other by h. I think of it as like a ratio. If we imagine in some imaginary universe that E and v r...

Bryan Jiang 1F

In the case you mentioned, yes, the molecular formula and empirical formula would be the same. You can tell if a molecular formula is also the empirical formula if you cannot further simplify the molecular formula to lower whole number ratios.

Bryan Jiang 1F

Yes, you should still get the same answer. Be careful though, make sure the energy required to remove an electron is 3.61 X 10^-19 J (negative 19, not positive 19). I don’t know if that was the source of your error, but I tried calculating the way you mentioned and still ended up with 551nm both way...

Bryan Jiang 1F

I understand that when the energy of photon is less than the threshold energy, no electron will be emitted no matter the rate and how many photons of that same energy hits the electron. My question is wanting to know where the energy of the photons go. Perhaps it dissipates as heat, but I don’t know...

Bryan Jiang 1F

I remember the example we used in class, but I am unsure how to tell which is which. One is when all measurements are close together, but not the desired amount? The other is when all the measurements are on target? Accuracy means how close your measurements are to the true/correct value . Precisio...

Bryan Jiang 1F

so the decimal is what sig figs revolves around correct? aka when in doubt just look and see the importance of a decimal? Yes, it could help thinking of sig figs like that when looking for the decimal and the numbers that come before it. However, keep in mind situations where numbers only come afte...

Bryan Jiang 1F

I believe that the actual yield must always be given since multiple factors (side reactions, impurities, sticking to side of beaker, etc.) can affect how much product the reaction will actually yield. Even if there were a way to calculate actual yield from taking into account every possible variable...

CHEMISTRY COMMUNITY

Search found 37 matches

Re: Porphyrin Ligand

Re: Shape of AX5E

Re: E3

Re: electron configuration of Palladium

Re: Molecular Shape

Re: Chelate

Re: VSPER MODEL FOR IODINE TRICHLORIDE

Re: Correct Dipole Depiction

Re: Carbon Monoxide Lewis Structure

Re: self-test 3.13B

Re: Covalent Bonds

Re: Does Sulfur or Phosphorus have a larger ionization energy?

Re: Electronegativity

Re: Why can't hydrogen be a central atom? [ENDORSED]

Re: radicals [ENDORSED]

Re: Module Questions 21 and 22

Re: Midterm Topics [ENDORSED]

Re: The order for s,p,d

Re: Electron Configuration Orders?

Spin Direction [ENDORSED]

Re: Quiz #2 Question #2 B

Re: Balmer and Lyman Series

Re: Test Time

Re: de brogile equation

Re: finding frequency from Einstein's equation [ENDORSED]

Re: Wavelength= (h/p) [ENDORSED]

Re: Homework #1.7 [ENDORSED]

Re: Balmer and Lyman Series

Re: Memorizing spectrum

Re: Atomic Spectroscopy [ENDORSED]

Re: Planck's Constant

Re: Empirical and Molecular the same [ENDORSED]

Re: Video module worked example [ENDORSED]

When photon energy is less than threshold energy

Re: Accuracy vs Precision

Re: 300 vs 300. [ENDORSED]

Re: Actual Yield [ENDORSED]