CHEMISTRY COMMUNITY

Kelly Hollman

On test #3 Q6B, how do we order the cations Li+, Ca2+, Cs+, Ba2+ in order from least to most polarizing power? I'm especially having trouble with putting Cs+ and Ba2+ in the right order.

Kelly Hollman

It is the least polarizable because it is the smallest anion in that problem. Chlorine (even without the charge) is the smallest (remember that atomic radius decreases as you go across the periodic table!).

Kelly Hollman

Oxoacids, in particular, more readily lose H+ IF the resulting anion (the anion that results when H+ is released) is stabilized by electron withdrawing atoms. These electron withdrawing atoms, a.k.a atoms with greater electronegativities, delocalize and stabilize the negative charge of the anion. J...

Kelly Hollman

(As mentioned in the coordination compounds review session yesterday) The molecular geometry will not allow all three oxygens to be binding sites. If you think about the trigonal planar structure and angles, it is impossible to have more than two oxygens close enough to each other AND have them bond...

Kelly Hollman

A coordination number is associated with the entire complex -- for example, if the TM has a monodentate ligand as well as a bidentate ligand, the coordination number will be 3.

Polydentates refer to the number of bonding areas (e.g., if there are lone pairs available for bonding) in a ligand.

Kelly Hollman

I don't believe that resonance structures should matter when determining if it is an acid or a base.

Kelly Hollman

How are disassociation and stabilization of acids related? I'm just a little confused as I read somewhere that higher electronegativity allows for acids to disassociate more easily, and thus causes them to be stronger acids. However, I also read that higher electronegativity allows for higher stabil...

Kelly Hollman

Just keep in mind that Ka = Kforward rxn/Kreverse rxn When you have a higher Ka, then you have more products (e.g., more H+ ions). This increases the pH (more acidic). Vice versa, when you have a lower Ka, you have more reactants -- there aren't as many H+ ions being produced. This lowers the pH (le...

Kelly Hollman

As electronegativity increases, inductive properties increase. This was mentioned in my discussion but I also don't recall the term itself being mentioned too often (if at all) in lecture. In lecture, we did learn that as electronegativity increases, stabilization is stronger, and those acids will b...

Kelly Hollman

From the review session about coordination compounds I attended yesterday, I believe it was mentioned that such cases are unlikely, so don't worry about them for the final.

Kelly Hollman

Check out Ch 12.1 and 12.2 in the book (6th edition; otherwise, there are likewise chapters in the 7th ed.) To summarize (taken directly from the book): Lewis Acids and Bases A Lewis acid is an electron pair acceptor . A Lewis base is an electron pair donor Bronsted-Lowry Acids and Bases An acid is ...

Kelly Hollman

Definitely look at the naming conventions chart on Dr. Lavelle's website: https://lavelle.chem.ucla.edu/wp-conten ... pounds.pdf

Kelly Hollman

They are the same -- just different naming conventions (one is newer, I think). It's on the naming coordination compounds chart from Dr. Lavelle's website.
https://lavelle.chem.ucla.edu/wp-conten ... pounds.pdf

Kelly Hollman

All the angles are 90 degrees even with the two lone pairs! Keep in mind than when there is only one pair but five other atoms bonded to the central atom, the angles do become less than 90 degrees. (square pyramidal)

Kelly Hollman

Danny Elias Dis 1E wrote:How many lone pairs are possible when the molecule is in the trigonal planar shape?

There can be 3 regions for this shape, but I think we've only seen molecules in this shape with one lone pair, e.g. SO2, a bent shape.

Kelly Hollman

I think we should be able to figure out the hybridization of the central atom based on the electron geometry but also, there's a chart in our text book (table 4.2) that has been really helpful for me and might help you out too!

Kelly Hollman

Distance and charges!

Kelly Hollman

The direct wedge is coming out of the page and the hatched wedge is going into the page!

Kelly Hollman

Fluorine needs on electron to fulfill an octet, so taking an electron away from it would be difficult and unlikely. A double bond between B and F would require that positive charge for Fluorine, so in this case, it won't happen.

Kelly Hollman

You can think about it as formal charge = "should" - "has".
What your atom should have are the number of valence electrons according to the periodic table.
What your atom, when bonded, actually has are: (lone pair electrons) + (1/2)*(the number of bounded electrons).

Kelly Hollman

To start finding the structures of this acid, you should first, according to the book, "choose as the central atom the element with the lowest ionization energy." Here, oxygen has the lowest ionization energy (besides Hydrogen, which shouldn't be considered as the central atom). Oxygen as ...

Kelly Hollman

Yup, and remember how iconic bonds are different from covalent bonds (which are between non-metals)

Kelly Hollman

They don't have "space" to fill an octet. They only have room for 2 electrons in the outershell as they have S orbitals only!

Kelly Hollman

They release energy when they are bound!

Kelly Hollman

I agree, kg is the SI unit for mass.

Kelly Hollman

I believe they are related through the Rydberg equation V = r (1/(n1^2) - (1/(n2^2)). When you calculate frequency, you may plug it into C = wavelength x frequency and solve for the wavelength. These wavelengths would then correspond to the wavelengths you see on figure 1.10. But keep in mind of the...

Kelly Hollman

You can use dimensional analysis! The total energy multiplied by 1 photon / energy (obtained from E = hv)

Kelly Hollman

I agree, you need to use the Debroglie equation because they give you velocity.

Kelly Hollman

I agree, it's asking for the mass of the electron.

Kelly Hollman

I believe you can try converting MHz to Hz!

1 MHz = 1000000 Hz

Kelly Hollman

I believe the net amount will be moles of product (gas) - moles of reactant (gas)

Kelly Hollman

Use the smallest amount of sig figs you find in the given numbers. For example, if you are given 20.0 grams and 156.6 grams, you'd use three sig figs in your answer (20.0 has three, 156.6 has four.)

Kelly Hollman

Yes, exactly. Each percentage is for each individual element of the vitamin.

CHEMISTRY COMMUNITY

Search found 33 matches

Least to most polarizing power?

Re: Test 3

Re: Disassociation and stabilization?

Re: Ligands

Re: Polydentate and Coordination Number?

Re: Resonance Structures

Disassociation and stabilization?

Re: Ka Formula

Re: Inductive Effect

Re: Transition Metal

Re: Lewis Acids and Bronstead Acids

Re: Anionic ligands

Re: Cyanide

Re: Square Planar Angles

Re: tetrahedral vs trigonal planar

Re: hybridization for VSEPR

Re: Dipole Dipole Forces

Re: Distance from Central Atom

Re: Boron Trifluoride class example

Re: Formal Charge Tricks

Re: The center atom

Re: Question regarding ionic bonds

Re: Exceptions

Re: bound atoms

Re: Equation units

Re: Series and Wavelengths

Re: Number of photons

Re: Homework Question 1.33 (6th Ed)

Re: de Broglie Relationship

Re: Problem 1.9 6th Edition

Re: Audio Visual Focus Topics Balancing Chemical Equations Pre Assessment

Re: Mass Percent Composition

Re: Audio Visual Focus Topic Empirical and Molecular Formulas Pre-Assessment