C2 Electronic Structure

Question 1

Electron shell rules (3)

Answer 1

1. Electrons occupy shells (energy levels)
2. The lowest energy levels are always filled first
3. Only a certain number of electrons are allowed in each shell
   (1st shell - 2 electrons, 2nd shell - 8 electrons, 3rd shell - 8 electrons)

Question 2

Working out electronic structures

Answer 2

See page 20

Question 3

Complete this sentence

Elements in the same group have the same number of…….

Answer 3

……..electrons in their outer shell.

Question 4

The periodic table tells you nitrogen has 7 protons.

How many electrons does it have?

Answer 4

7

Question 5

The periodic table tells you that nitrogen has 7 protons.

How are the electrons arranged over the shells?

Answer 5

It has 7 protons, so it must have 7 electrons.

The first shell can only take 2 electrons and the second shell can take a maximum of 8.

So 2 electrons go in the first shell and the remaining 5 will go in the second shell.

Question 6

What is the electronic structure of nitrogen?

7 protons

Answer 6

2.5

Because there are 2 in the first shell and 5 in the second shell

Question 7

What information about electronic structure do we get from an elements period?

Answer 7

The period is the same as the number of shells which contain electrons.

Question 8

What information about electronic structure do we get from an elements group?

Answer 8

The group number tells you how many electrons occupy the outer shell of the element.

Question 9

How can we use group and period to work out electronic structure for an element?

Use example sodium period 3, group 1

Answer 9

It has 3 shells occupied (period 3), so the first two shells must be full (2,8, )

It has 1 electron in its outer shell (group 1), so it’s electronic structure is 2.8.1

Question 10

What can an elements position in the periodic table help you predict?

Answer 10

The reactivity of the element

Question 11

What does the way an element reacts depend on?

Answer 11

The number of shells in its outer shell

Question 12

What do we know about the way elements with the same number of electrons in their outer shell react?

Answer 12

They react in similar ways

Question 13

What affects how reactive an element is?

Answer 13

The number of shells that an element has.

Question 14

What effect does more shells have on group 1 element have?

Answer 14

The more shells the more reactive it is

Question 15

What effect does an increase in the number of shells have on group 7?

Answer 15

More shells make the element less reactive

Question 16

Give the electronic structure of potassium (atomic number 19) (1 mark)

Answer 16

2.8.8.1 or can draw shells see answer page 111