Question

how to find out atomic number of helium
?​

Answer 1

Answer:

number of protons = atomic number. number of electrons = atomic number. number of neutrons = mass number - atomic number.

atomic number is 2, so it has two protons in its nucleus. Its nucleus also contains two neutrons. Since 2 + 2 = 4, we know that the mass number of the helium atom is 4.

Answer 2

Answer:

atomic number of helium is 2

Explanation:

number of protons = atomic number. number of electrons = atomic number. number of neutrons = mass number - atomic number.