An element has atomic number 10 and an atomic number mass of 20. how mamy neutrons are in the atom of this element?

10

Explanation:

The atomic mass = 20

The atomic number = 10

The number of neutrons = mass - number = 20 - 10 = 10

This formula is always true. There are no exceptions.

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.