Which element forms a compound with chlorine with the general formula MCl?

(1) Rb (3) Re

(2) Ra (4) Rn

Answer is (1) - Rb.

To form MCl, The cation should have + 1 as the charge. According to the given choices, Rb can form + 1 ion by losing an electron. It is because Rb is in 1st group of the periodic table.

The electron configuration of Rb is [Kr] 5s¹. After losing as electron, Rb has electron configuration as [Kr].

The compound is RbCl (Rubidium Chloride) which has a molar mass of 120.921 g/mol.

Rb forms a c ok compound with the general formula MCI.