Periodicity

Question 1

What is the periodic table arranged into?

Answer 1

Rows and columns

Question 2

What do the rows represent?

Answer 2

Periods

Question 3

What do the columns represent?

Answer 3

Groups

Question 4

What do all elements in a period have in common?

Answer 4

They have the same number of electron shells

Question 5

What do all elements in a group have in common?

Answer 5

They have the number of electrons in the outer shell

Therefore, they have similar properties

Question 6

Which blocks is the periodic split into?

Answer 6

s,p,d,f

Question 7

What happens to the atomic radius across a period?

Answer 7

The atomic radius decreases

Question 8

Why does the atomic radius decrease across a period?

Answer 8

The number of protons increases as well as the positive charge of the nucleus
The electrons are pulled closer

Question 9

What factors affect the melting point?

Answer 9

Bond strength

Structure

Question 10

What is the trend in the melting and boiling points of sodium, magnesium and aluminium?

Answer 10

Their melting and boiling points increase

Question 11

Why do the melting and boiling points increase for sodium, magnesium and aluminium?

Answer 11

The metallic bonds become stronger due to the increasing positive charge, increasing number of delocalised electrons and a decreasing radius

Question 12

Why doe silicon have a high melting point?

Answer 12

It is macromolecular

there are strong covalent bonds

Question 13

Why do phosphorus,sulfur and chlorine have low melting points?

Answer 13

They are molecular substances

They only have van der Waals forces which can be easily overcome

Question 14

Why does sulfur have a melting point than phosphorus and chlorine?

Answer 14

It is the biggest molecule

S8

Question 15

Why does argon have a very low melting point?

Answer 15

It exists as individual atoms

There are very weak van der Waals force

Question 16

What is the trend for the ionisation energy across a period?

Answer 16

The ionisation energy increases across a period due to the number of protons

Question 17

Why is there a slight drop in the first ionisation energy between group 2 and 3?

Answer 17

There is a new sub shell structure

The electron is being removed from a ‘p’ shell which is a higher energy level

Question 18

Why is there a slight drop in the first ionisation energy between group 5 and 6?

Answer 18

There is electron-pair repulsion

This makes it easier to remove the electrons as they are already repelling each other

Question 19

Why do Lithium and Beryllium have high melting points in period 2?

Answer 19

they both have metallic bonding

Question 20

Why do Boron and carbon have very high melting points?

Answer 20

They are macromolecular

Question 21

Why do nitrogen and oxygen have low melting points?

Answer 21

They are molecular gases

They have weak van der Waals forces

Question 22

Why does Neon have a very low melting point?

Answer 22

It is a monoatomic gas