Question

which of the following elements is an alkali metal?

• sodium
• magnesium
• calcium
• mercury

Explanation:

Alkali metals are in Group 1 of the periodic table. Sodium is in Group 1 and is an alkali - metal. Magnesium is an alkaline - earth metal (Group 2), calcium is also an alkaline - earth metal (Group 2), and mercury is a transition metal.

Answer:

A. sodium