2) Unit 1 - Atomic Orbitals, Electronic Configurations and The Periodic Table

Question 1

what is the 1st quantum number called, what is its symbol and what does it show?

Answer 1

• Principle quantum number
• ‘n’
• denotes the energy level an electron is found

Question 2

what is the 2nd quantum number called, what is its symbol, how can you work it out and what does it show?

Answer 2

• Angular momentum Quantum number
• ‘l’
• l= n-1
• determined the shape of molecule

Question 3

what is the 3rd quantum number called, what is its symbol, how can you work it out and what does it show?

Answer 3

• Magnetic Quantum Number
• ‘m’
• (-l…0…+l)
• shows the number of degenerate orbitals in a shell

Question 4

what is the 4th quantum number called, what is its symbol, what are its possible values and what does it show?

Answer 4

• Spin Quantum Number
• ’s’
• +1/2 or -1?2
• shows the orientation of electrons

Question 5

What are the shapes and names of orbitals if:

L=0
L=1
L-2

Answer 5

L=0, s orbital, spherical

L=1, p orbital, dumbbell

L=2, d orbital, 4 lobes

Question 6

decribe what the orbitals 2px, 2py, and 2pz look like

Answer 6

2px - dumbbell lying on the x axis
2py - dumbbell lying on the y axis
2pz - dumbbell lying on the z axis

Question 7

describe what the following orbitals look like:

dx2-y2
dz2
dxy
dyz
dxz

Answer 7

dx2-y2 - 4 lobes lying directly on the x and y axis in a horizontal plane

dz2 - 2 lobes lying vertically on the z axis and ring around the lobes

dxy - horizontal plane, lobes lying in-between x and y axis

dyz - vertical plane, lobes lying in-between y and z axis

dxz - vertical plane, lobes lying in-bwteen z and x axis

Question 8

what is the electron configuration

Answer 8

the arrangement of electrons in the energy levels and orbitals of an atom - essentially the sequence of 4 quantum numbers

Question 9

list in order of increasing energy, the way electrons follow when filling orbitals e.g. 1s> 2s …….. 3d

Answer 9

1s 2s, 2p, 3s, 3p, 4s, 3d

Question 10

Name and describe the 3 principles followed when making orbital box notations

Answer 10

Aufbau’s: electrons fill the orbitals in order of increasing energy e.g. 1s> 2s> 2p

Paulis: can only have two electrons in each orbital which must have opposite spins

Hunds: in degenerate orbitals, electrons fill singularly before pairing occurs

Question 11

What groups are the s,p, d and f in the periodic table

Answer 11

s - alkali metals
p - non metals
d - transition metals
f - lanthanides and actinides

Question 12

what is the ioniaation energy

Answer 12

energy required to remove one mole of electron from one mole of gaseous atoms

Question 13

The ionisation energy for nitrogen is greater than that of oxygen, even though nuclear charge of oxygen is greater than that of nitrogen. Why?

Answer 13

N 1s2, 2s2, 2p3
O 1s2, 2s2, 2p4

Nitrogen has a reletavily stable half shell where as oxygen does not
So it is easier to remove the 4th ‘p’ electron from the 2p orbital of oxygen than it is to remove an electron from Nitrogens half filled shell