GChem: Atomic structure and periodic trends

Question 1

Bohr model, quantized energy states

Is there greater E jump from n=1 to n=2 or n=2 to n=3?

Answer 1

n=1 to n=2

Question 2

The energies of discrete energy levels were given by Bohr in the following equation

Answer 2

En = (-2.178 *10^-18J)/n^2

n represents energy levels of the electron

Question 3

Using Bohr’s model and different discrete energy levels, how can we calculate wavelength of photos emitted?

For this topic we need to think about how ____ and ____ have an inverse relationship according to a certain physics equation…

Answer 3

Subtract initial energy level of electron from the final energy of the electron
change in E is negative indicates that E is being released as electron falls to ground state, if change in E pos that means E absorbed by the electron

Then one can plug into the equation
Change in E = h(c/lambda)
plank’s constant h = 6.63 * 10^-34 J*s
c is the speed of light -> c = 3x10^8 m/s

Question 4

What is a Bohr atom?

Answer 4

One that contains only one electron
example of atom that is NOT BOHR ATOM = H+ because it has pos charge from losing the one electron and now has no electrons at all

Question 5

Is spectroscopy a form of separation?

Answer 5

NO

Question 6

Diamagnetic

Answer 6

all electrons spin-paired so even number of electrons

Such an atom would be repelled by an externally produced magnetic field

Question 7

Paramagnetic

Answer 7

When an atom’s electrons are not all spin-paired

Attracted into externally produced magnetic fields

Question 8

If you ever need to write the electron configuration for an element in the d block…
for the f block…

Answer 8

for d, subtract 1 from n

for f, subtract 2 from n

Question 9

Which elements have that weird d orbital electron configuration rule?

Answer 9

Cr, Mo

Cu, Ag, Au

Question 10

Isoelectric

Answer 10

having the same numbers of electrons or the same electronic structure
Ex. If F gains an electron, it has the same electron configuration at Ne

Question 11

Electrons that are ionized from transition metals come from…

Answer 11

the s orbital before the d orbital

Question 12

Electron configuration of Ta

Pr?

Answer 12

4f14 5d3 6s2

[Xe]6s24f44

Question 13

Where are the alkaline earth metals, alkali metals, halogens, rare earth metals in periodic table?

Answer 13

alkaline earth metals - Second group
alkali metals - First group
halogens - Second to last group
rare earth metals - F block

Question 14

Electron affinity

and trend

Answer 14

Energy associated with the addition of an electron
If energy is released when electron is added, then EA is negative, but if energy is required in order to add the electron, the electron affinity is positive (When atom has closed shell OR subshell)
Halogens has a large negative EA bc they get the desired octet

Electron affinities generally become more neg across a period left to right (exception is noble gases and other anomalies)

Question 15

Electronegativity
What is it? What is the trend?
List the highest EN atoms

Answer 15

Atom’s ability to pull electrons to itself when if forms a covalent bond
The greater this tendency to attract electrons, the greater the atom’s electronegativity

Electronegativity basically behaves like ionization energy
Increases diagonally up across the periodic table

F>O>N = Cl >Br >I> S> C=H
Fonclibrisch

Question 16

Acidity

Answer 16

How well a compound donates, protons, accepts electrons, or lowers pH
So if have HX and is dissociates into H and X-, acidity is based on stability of conjugate base X-, how comfortable is it with that negative?
The most electronegative the element bearing the negative charge is, the more stable the anion will be so acidity increases left to right across periodic table
Vertical trend depends on size, the larger the anion, the more negative charge can be delocalized

Question 17

List the trends for:

Atomic radius, Ionization energy, Electron affinity, Electronegativity, Acidity

Answer 17

Check pics 5/8/21 or page 80 of MCAT general review

Question 18

I skipped this (may be extra?)
Electrostatic attraction relationship
Equation for Zeff

Answer 18

Fe proportional to 
(Zeff + C)/r^2
Zeff = Z - Core e- 
Z -> protons 
Core e- -> Non-valence e- like for ex. for Carbon if had. [He] 2s2 2p2
Then since He has 2 e- 
so do Zeff = 6 - 2

Question 19

Equation for energy of a photon

Answer 19

E = hf = hc/lambda

Question 20

What does an absorption and emission spectrum look like?

Answer 20

Absorption looks like rainbow with black lines

Emission looks black with colored lines

Question 21

List order to light wavelengths

Answer 21

Gamma, X-ray, UV V (B,G,Y,O,R) IR, Microwave, Radio wave

Gamma most E, most frequency, lowest wavelength