Predicting reactivity using the periodic table

In a nutshell

During a chemical reaction, elements are keen on combining with another element to form a new molecule. To what extent an element is keen on reacting depends on its reactivity. You can predict the reactivity of elements once you know the trend.

Group 0

Group $0$ elements are located in the last column of the periodic table. They are known as the noble gases and are all inert.

Group $0$ elements include:

Helium
Neon
Argon
Krypton
Xenon
Radioactive radon
Oganesson

Science; The periodic table and properties of materials; KS3 Year 7; Predicting reactivity using the periodic table

Group 1

Group $1$ metals are located in the first column of the periodic table and are known as alkali metals.

Group $1$ metals become more reactive going down the group. They react with water to form an alkaline solution.

Example

Lithium fizzes when it reacts with water. However, rubidium explodes when in contact with water.

Group 7

Group $7$ elements are located in the second to last column of the periodic table. They are known as the halogens.

The reactivity of the halogens down the group is opposite to that of the alkali metals. Group $7$ elements become less reactive going down the group.

Example

Chlorine reacts vigorously with metals whereas iodine reacts very slowly with metals.

Science; The periodic table and properties of materials; KS3 Year 7; Predicting reactivity using the periodic table

A.	Alkali metals (Group $1$ )
B.	Halogens (Group $7$ )
1.	Less reactive
2.	More reactive