Question

which statement is true about all the atoms of a given element?
a they all have the same number of protons.
b they have the same number of neutrons.
c they are the same size as the atoms of all other elements.
d they can have a different number of protons.

Explanation:

The atomic number of an element is defined by the number of protons in its atoms. All atoms of a given element have the same atomic number, so they have the same number of protons. Isotopes of an element have different numbers of neutrons. And atoms of different elements have different sizes.

Answer:

A. They all have the same number of protons.