2.2.1 Electron Structure

Question 1

How many electrons fill the first 4 shells?

Answer 1

1st - 2
2nd - 8
3rd - 18
4th - 32

Question 2

How do you work out the no of electrons in each shell?

Answer 2

Number of e- = 2n^2

Where n = shell no

Question 3

What is an orbital?

Answer 3

A region of space within an atom that can hold up to 2 electrons with opposite spin

Question 4

What shapes are orbitals?

Answer 4

S-orbitals are spheres
P-orbitals occur in sets of 3 with equal energy, they are dumbell shaped and lie at right angles to each other

Question 5

How many orbitals make up sub shells?

Answer 5

One orbital in s-sub shell
3 orbitals in p-subshell
5 orbitals in d-sub shell
7 orbitals in f-sub shell

Question 6

How many electrons fill sub shells?

Answer 6

S = 2
P = 6
D = 10
F = 14

Question 7

What is the sub shell filling order?

Answer 7

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p

Question 8

What are the exceptions to the usual electron configuration pattern?

Answer 8

Chromium-24 and copper-29
Cr has 1 electron in 3d and 4s
Cu has one electron in 4s