CHEMISTRY COMMUNITY

pauline young 1L

as a general rule, i think if there are more than one lone pairs on the same atom, it would still be considered a monodentate

pauline young 1L

no i don't think two atoms can have a resonance structure

pauline young 1L

do we need to know any super acids for the final?

pauline young 1L

other than Noble Gases i don't think there are any other exceptions

pauline young 1L

adding onto this reply for water, even though there are two lone pairs, both are on the O. Since the lone pairs are on the same atom, it doesn't matter that there are two lone pairs, its still only monodentate

pauline young 1L

i think you should memorize some of the common strong and weak acid/bases. other than that, there are some trends you can pick up on. for example, Dr. Lavelle mentioned that if there's a N involved, its probably a weak base.

pauline young 1L

like the others said, i don't think it is necessary to read through the entire textbook (unless you want to). If you're just trying to study for the final, you should be good by reading just the sections corresponding to the homework and are mentioned in the outline.

pauline young 1L

i would only focus on what is included in his outlines.

pauline young 1L

I remember Dr. Lavelle mentioning how we should know how the cisplatin works, but i don't think we need to know anything more than the extent of what is mentioned above ^

pauline young 1L

i think knowing that there are acids and bases that go beyond the scale is enough, we don't need to specifically memorize any cases of that.

pauline young 1L

i think we just have to know how to count them, know which one is stronger, and their different interactions with the internuclear axis

pauline young 1L

its essentially 3 sp2 orbitals in one plane (imagine them laying flat) and then one p orbital point up and one point down.

pauline young 1L

there are more electron overlaps in sigma bonds which make them a lot stronger than pi bonds and thus requiring more energy to break

pauline young 1L

probably save to know it just in case, especially for this acid and base section

pauline young 1L

yes the 2 lone pairs on oxygen in H2O are both able to form their own respective hydrogen bond with other hydrogens.

pauline young 1L

does anyone know if this test is cumulative? are we gonna be tested on some info from before the midterm

pauline young 1L

i think we are going to learn more about sigma and pi bonds in class on monday

pauline young 1L

not sure if this is what you're asking about, but i think you keep the bond lines the same. to show dipole you would draw an additional line with an arrow to show which side is positive and which is negative.

pauline young 1L

yes! as long as you remember that they mean the same thing, you should be able to use them interchangeably.

pauline young 1L

as long as you understand that if its just E, that means there's an invisible 1 there, it shouldn't really matter whether or not you actually put the 1 in when writing the answer

pauline young 1L

induced dipole moment is caused whej a polarizing molecules gets close enough to a non polarized molecule that it disturbs it’s electron arrangement of the non polarized molecule

pauline young 1L

i think it will start on outline 3 from where the midterm cut off point was

pauline young 1L

Matt F wrote:Test 2 is in week 8, right? I'm sure some of the prior material will be on it (at least the stuff on chemical bonds) since otherwise it'll only be covering a week or so of material.

yea test two is week 8!

pauline young 1L

there are lots of different factors affecting bond strength such as bond length, number of lone pairs, bond multiplicity and more

pauline young 1L

we are not responsible for knowing exact electronegative numbers, as long as you know the general trend you will be fine!

pauline young 1L

triple bonds are shorter than double which is shorter than single. then, the shorter the bond lengths are, the closer the electrons are being held together and therefore the stronger the bonds since more energy is needed to break the bond.

pauline young 1L

since you are trying to break bonds, energy is always required (its always going in) and therefore it is always going to be positive.

pauline young 1L

yes since electrons in the s orbital of the same shell us located closer to the nucleus than those of p orbital, the nuclear charge is shielded by the s electrons.

pauline young 1L

you can use it to find the energy amount of a particular energy level, which can then allow you to calculate the energy difference or the frequency of electron when it goes from one energy level to another

pauline young 1L

the effective nuclear charge is smaller than the actual nuclear charge because the inner electrons shield or block the outer electrons from experiencing the full nuclear charge.

pauline young 1L

a little off topic but C, N, O, F are strict followers of the octet rule!

pauline young 1L

yes those topics will most likely be showing up on the midterm

pauline young 1L

if it was on the past midterm exams, then there's a pretty good chance it will also be on this years

pauline young 1L

normally, ground state electrons would try to automatically obtain a upward arrow spin. so the fact that it went to a downward arrow first even thought the orbital is not yet containing an upward arrow would show that the electron is in an excited state

pauline young 1L

it wasn't stated in the learning outline so i am assuming we do not have to know how to do that

pauline young 1L

5 problems from either section should be fine

pauline young 1L

electrons further from the nucleus have more energy

pauline young 1L

the examples he gave in class were copper and chromium, however, this does not mean those elements are the only exceptions, period 5 on the periodic table follows the same trend.

pauline young 1L

you can first draw lines to represent number of orbitals in each sub shell, then depending on how many valence electrons there are you can decide how many arrows you need to draw in. in terms of where to draw the arrows, fill each line with 1 arrow first and then if there are more arrows that need t...

pauline young 1L

in addition to that Dr, Lavelle always draws out the n levels on his board using lines. as the energy level increases, the distance between the new energy level and previous one decreases.

pauline young 1L

Yes you can them. Also side note that Rydberg constant/eqn works only for hydrogen atoms

pauline young 1L

Photoelectron spectroscopy works for other atoms as well but the Bohr model (first quantized model of the atoms) worked only for H

pauline young 1L

There isn’t a specific number where the frequency is enough to remove an electron. This would depend on the situation and the metals used. But in general when the energy per incoming photon is greater than an electrons threshold, the electron will be removed.

pauline young 1L

Because electrons are quantized (have fixed locations) and since light can interfere and diffract it can be said that light has wave like properties. Photoelectric effect (shows that when light is shone onto a metal surface, electrons could be ejected) shows the particle side of the duality for light.

pauline young 1L

Does anyone know where and when our grades for this class will be updated?

pauline young 1L

it could seem like a hassle preserving your decimals for every little step but if you don’t sometimes your final answer could be off by a few digits, which i’m not sure if that’ll result in points being docked, but my advice would be to definitely watch out for that!

pauline young 1L

the ones he went over in class are:
F=(1.8C)+32
and k= C+273.15

pauline young 1L

if you’re not looking for help on a specific topic but more like an overview of gen chem as a whole, i watched “the organic chemistry tutor”! it’s rly long but also covers a lot of topics

pauline young 1L

So if it’s 0s after the decimal: any 0 before actual numbers don’t count as sigfig but any 0 after the actual numbers do count. In addition, if the number is, say, 100 then sigfig is 1 digit. but if it’s 100. (notice the decimal) then the sigfig becomes 3 digits. if it’s 100.0 then it’s 4 and so on....

pauline young 1L

Hey, most of us have a pdf version of it. so if it’s not too distracting for you to use electronics in class, i think it’s a good idea to just open it up on your laptop and follow along during the lectures!

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