All atoms of the same element must have the same number of

protons.
neutrons.
compounds.
electrons.

Answer;

-Protons

All atoms of the same element must have the same number of protons.

Explanation;

As we know that any atom is represented as

here we have

z = atomic number = number of protons

A = mass number = number of neutron + number of protons

Now if we have atoms of same element then we can say that its atomic number will remain same

This shows that number of protons will not change in that case

So here correct answer will be

PROTONS

2b2t

explanation:

2b2t