Electron configurations and orbitals

Question 1

Principle quantum number

Answer 1

Each number which is given to each shell
Represented by ‘n’

Question 2

First shell closest to nucleus principle quantum number

Answer 2

n=1

Question 3

Second shell principle quantum number

Answer 3

n=2

Question 4

How is principle quantum number worked out?

Answer 4

The number of shells it is away from the nucleus
n=4 so 4th shell

Question 5

How to find the Maximum number of electrons each shell can hold

Answer 5

2n²
n=principle quantum number

Question 6

What are the regions electrons are found within a shell?

Answer 6

In atomic orbitals

Question 7

Atomic orbitals

Answer 7

Region around the nucleus of an atom that can hold up to 2 electrons with opposite spin

Question 8

S orbital

Answer 8

Spherical shape
Holds up to 2 electrons
In every single shell

Question 9

P orbital

Answer 9

Each sub shell has 3 p orbitals
Each p orbital is made up of 2 dumbbell shapes
So can hold up to 6 electrons in total (3 pairs)

Question 10

Which electron shells have a p orbital?

Answer 10

Every one except the 1st one

Question 11

D subshell

Answer 11

Can hold up to 10 electrons (5 pairs of opposite spin)
because there are 5d orbitals in a d subshell

Question 12

Which electron shells have d orbitals?

Answer 12

Every shell except the 1st and 2nd

Question 13

F orbitals

Answer 13

Every shell from 4 and above
7 which can hold up to 14 electrons in one F subshell

Question 14

Subshell

Answer 14

All of the orbitals of the same type in the same shell
Eg not just the singular p orbital but all 3 p orbitals

Question 15

Subshell energies

Answer 15

Moving away from the nucleus increases the subshells energy
Increasing energy from:
1s ————>3p

Question 16

Rules for filling atomic orbitals with electrons

Answer 16

Lowest energy levels (closest to nucleus) filled first
Up to 2 electrons in the same orbital but has opposite spins
Put each electron into individual orbitals before pairing them up
4s filled before 3d

Question 17

Why do we not pair up electrons in orbitals first?

Answer 17

Because electrons in the same orbital repel

Question 18

Filling orbitals

Answer 18

Always with lowest energy levels (closest to nucleus, so Quantum number 1)
Working way out to higher energy levels
spreading them out at first with 1 per orbital then matching them up

Question 19

How does filling electrons from lowest to highest energy level affect 3d and 4s?

Answer 19

4s at lower energy level than 3d
So fill 4s first
Yet write configuration in order of electron shells (not order of filling)
So just leave a gap for 3d, write 4s then go back if necessary
if the number of electrons finish at 4s eg in K and Ca just skip 3d and fill up 4s

Question 20

What elements have no electrons in the 3d orbital but electrons in the 4s orbital?

Answer 20

K and Ca

Question 21

Exceptions for electron filling when it comes to 3d being at a higher energy level than 4s?

Answer 21

Chromium and copper
Where you fill 3d first then 4s

Question 22

Why is in some atoms the 4s orbital at a lower energy level than 3d?

Answer 22

Because the energy of the quantum level is determined by the repulsion between the electrons and nucleus
3d is more compact than 4s
So electrons experience nuclear repulsion in 3d causing them to have a higher energy level

Question 23

Hund’s rule

Answer 23

Electrons occupy orbitals singularly before pairing up

Question 24

Pauli Exclusion Principle

Answer 24

2 electrons cannot occupy the same orbital unless they are of opposite spin

Question 25

Aufbau principle

Answer 25

Electrons in orbitals are filled from the lowest energy levels to the outer energy levels