How many covalent bonds does hydrogen form if each of its unpaired electrons participate in one bond?

A single hydrogen atom can form one covalent bond. A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. The atoms share valence electrons, which are in the atom's outermost shell. Hydrogen has one electron to share.Hydrogen has a 1s valence subshell, which can hold a maximum of two electrons. Hydrogen covalently shares this single electron with other atoms needing extra electrons to fill their valence shell.

It is both the conjugate base of carbonic acid H 2CO 3; and the conjugate acid of CO 2− 3, the carbonate ion, as shown by these equilibrium reactions: CO 2− so it is H 2CO 3