Elements can form covalent bonds and ionic bonds.

Covalent bonds can form between atoms of the same elements (i.e. H2). However, ionic bonds cannot do this. Covalent bonds are formed between two non-metals, whereas ionic bonds are formed between a metal and non-metal. Molecules formed by covalent bonds have a low melting point, whereas those with ionic bonds have a high melting point.

Explanation:

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds