What is the colour of sodium in a flame test?

• A blue
• B green
• C yellow
• D purple

The trend in the boiling points for these elements is similar to the trend in their melting points.

Predict a value for the boiling point of rubidium.

Caesium is another element in Group 1, located below rubidium.

Predict its melting point and how its reactivity compares to rubidium.

• Melting point: $.............{}^{\circ }C$
• Reactivity: $.............$

The elements in Group 1 have similar chemical reactions because they have the same number of

• A electrons
• B electron shells
• C outer electrons
• D protons

A student wrote these statements about the reactions of the Group 1 elements.

• The reactivity of the elements increases down the group.
• The elements form ions with a single negative charge.
• The formula of rubidium chloride is $RbCl$.
• The equation for the reaction of sodium with water is $2Li+2H_{2}O\to 2LiOH+H_2$.
• In the reaction between sodium and water, sodium acts as an oxidising agent.

Three of the statements contain one incorrect word.

Complete the table to show each incorrect word and the correct word that should be used to replace it.