5.1 - Electron Structure

Question 1

What are shells?

Answer 1

Energy levels

The energy increases as shell number increases

Question 2

What is the principal quantum number n?

Answer 2

The shell number or energy level number

Question 3

How many electrons are in shells 1, 2, 3, 4?

What is the formula for this?

Answer 3

2, 8, 18, 32

2n^2

Question 4

What are atomic orbitals?

Answer 4

Region around a nucleus that can hold up to two electrons, with opposite spins

Question 5

What do models visualise an atomic orbital as?

Answer 5

A region in space where there is a high probability of finding an electron.

Question 6

What can an electron be thought of as?

Answer 6

An electron can be thought of as a negative charge cloud with the shape of the orbital referred to as an electron cloud

Question 7

How may electrons can an orbital hold?

Answer 7

One or two electrons, but no more

Question 8

What are the different types of orbitals?

Answer 8

s-, p-, d-, f- orbitals

Each type of orbital has different shape.

Question 9

What are s-orbitals’ shape like?

Answer 9

In an s-orbital the electron cloud is within the shape of a sphere

Each shell from n=1 contains one s-orbital
The greater the shell number n, the greater the radius of its s-orbital

Question 10

What are p-orbitals’ shape like?

Answer 10

Electron cloud is within shape of a dumbbell.

Each shell from n=2 contains 3 p-orbitals

The greater the shell number n, the greater the radius of its s-orbital

Question 11

How many d-orbitals?

Answer 11

Each shell from n=3 contains five d-orbitals

Question 12

How many f-orbitals?

Answer 12

Each shell from n=4 contains 7 f-orbitals.

Question 13

What sub-shells are present in shell 1?

Answer 13

1s sub-shell

Question 14

What sub-shells are present in shell 2?

Answer 14

2s sub-shell

2p sub-shell

Question 15

What sub-shells are present in shell 3?

Answer 15

3s sub-shell
3p
3d

Question 16

What sub-shells are present in shell 4?

Answer 16

4s sub-shell
4p
4d
4f

Question 17

How do orbitals fill?

Answer 17

In order of increasing energy:
1s 2
2s 2, 2p 6
3s 2, 3p 6
4s 2 , 3d 10 , 4p 6, 4d 10, 4f 14

Question 18

Why does 3d sub-shell fill after 4s sub-shell?

Answer 18

Because the energy level of the 3d is higher than the energy level of 4s when filling