Question

an atom has atomic mass number 12 what is its valency and name the element

Answer 1

the element is carbon and it is tetra valency.

Answer 2

An atom has atomic mass number 12 what is its valency and name the element.

We know that

Atomic mass = number of protons + number of neutrons

and

Atomic number = number of electrons = number of protons

So,

The element having mass 12

number of electrons = 12

number of protons = 12

Now,

Atomic mass = number of protons + number of neutrons

The element is carbon (C)