How many neutrons does the element H have?

Answer 1

It depends on the isotope. Ordinary hydrogen has no neutrons at all.

However, deuterium is hydrogen with one neutron, and tritium is hydrogen with two neutrons.

Deuterium is about twice as heavy as ordinary hydrogen, and tritium is three times as heavy, so hydrogen compounds in which some of the hydrogen is one or both of these heavier isotopes is correspondingly heavy. An example is heavy water.

Normally, in formulas, the letters D and T are used instead of H to indicate deuterium and tritium.

So, H has no neutrons.