Question

which element is classified as an alkali metal?
○ rb
○ sr
○ zr
○ cl

Explanation:

Alkali metals are in Group 1 of the periodic table. Rb (Rubidium) is in Group 1, Sr (Strontium) is in Group 2 (alkaline earth metal), Zr (Zirconium) is a transition metal, and Cl (Chlorine) is a halogen. So Rb is an alkali metal.

Answer:

A. Rb