Chapter 5 - Electron Structure

Question 1

What is an atomic orbital?

Answer 1

An atomic orbital is a region around the nucleus that can hold up to two electrons, with opposite spins.

Question 2

How many electrons can a p-sub shell hold?

Answer 2

Six (3 orbitals each containing 2 electrons of opposite spins)

Question 3

Give the number of electrons that fill the first 4 energy shells.

Answer 3

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

Question 4

What happens to energy as the shell number increases?

Answer 4

The energy increases

Question 5

What is the shell number called?

Answer 5

principal quantum number, n

Question 6

What is the shape of the s orbital electron cloud?

Answer 6

A sphere

Question 7

What happens to the size of the s orbital when the shell number is greater?

Answer 7

The radius of the s orbital increases

Question 8

How many s orbitals does each shell contain?

Answer 8

1

Question 9

What is the maximum number of electrons that an s orbital can hold?

Answer 9

2

Question 10

What is the shape of the electron cloud of a p orbital?

Answer 10

Dumbbell shaped

Question 11

What happens to the p orbital as the shell number increases?

Answer 11

The p orbital is further away from the nucleus

Question 12

How many p orbitals can there be in an energy level from n=2?

Answer 12

3

Question 13

How many d orbitals can there be in an energy shell from n=3?

Answer 13

5

Question 14

How many f orbitals can there be in an energy shell from n=4?

Answer 14

7

Question 15

What are orbitals of the same type grouped as?

Answer 15

Sub shells

Question 16

How many electrons can a d sub shell hold?

Answer 16

10 (5 orbitals each containing 2 electrons)

Question 17

How many electrons can an f sub shell hold?

Answer 17

14 (7 orbitals)

Question 18

How many electrons can an s sub shell hold?

Answer 18

2 electrons, 1 orbital

Question 19

Why does a 4s sub shell fill up before a 3d sub shell?

Answer 19

A 3d sub shell is at a higher energy than the 4s sub shell

Question 20

Why must the electrons filling up orbitals have opposite spins?

Answer 20

They help to counteract the repulsion between the negative charges of the two electrons

Question 21

Why do electrons fill up orbitals singularly before pairing up?

Answer 21

This prevents repulsion between paired electrons as having minimal repulsion means the arrangement is most stable and of the lowest energy

Question 22

How are cations formed and what are they also known as?

Answer 22

They are known as positive ions and are formed when an atom loses electrons

Question 23

How are anions formed and what are they also known as?

Answer 23

They are known as negative ions and are formed when an atom gains electrons

Question 24

Why are electrons lost from the 4s orbital first?

Answer 24

The 4s orbital is of a higher energy when FILLED and so electrons are removed from it first

Question 25

Where is the s-block on the periodic table?

Answer 25

groups 1 and 2 (far left)

Question 26

Where is the p-block on the periodic table?

Answer 26

groups 13-18 (far right)

Question 27

Where is the d-block on the periodic table?

Answer 27

groups 3-12 (centre block of 10 groups)