Group 1 - physical properties

Group 1 contains elements placed in a vertical column on the far left of the periodic table. The elements in group 1 are called the alkali metals.

Periodic table with group 1 elements coloured in red.Group 1 is on the left-hand side of the periodic table

The alkali metals share similar physical properties. For example, they:

  • are soft (they can be cut with a knife)
  • have relatively low melting points
  • have low densities
Question

The table shows the melting points of five alkali metals.

Use this information to describe how melting point changes in group 1.

ElementMelting point (°C)
Lithium, Li180
Sodium, Na98
Potassium, K63
Rubidium, Rb39
Caesium, Cs28

Going down group 1, the melting point decreases.

Question

Francium, Fr, is below caesium in the periodic table.

Use the information in the table above to predict the melting point of francium. Explain your answer.

The melting point of francium will be around 23-27°C. This is because francium is below caesium in the periodic table, so it should have a lower melting point as melting point decreases going from one element down to the next.