Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?

Helium atom has an atomic mass of 4u and two protons in its nucleus. How many neutrons does it have ?

Helium atom has an atomic mass of 4u and two protons in its nucleus. How many neutrons does it have?

Helium atom has an atomic mass of 4 u and two protons in its nucleus. Howmany neutrons does it have ?

Lithium atom has atomic mass 6 and has 3 protons in it nucleus. How many neutrons does it have? Write down its electronic configuration.

The mass number of an atom is 31. The M shell of this atom contains 5 electrons. How many neutrons does this atom have?

The atom of which element has no neutron in its nucleus ?

An atom has mass number A and atomic number Z. How many neutrons are present in its nucleus ?