1. two atoms are the same element if they have the same
a. atomic number
b. number of neutrons
c. charge
d. number of electron shells

Same number of neutrons.

Explanation:

What defines an atom as a certain element is the number of neutros in its nucleus. Some atoms have a different number of neutrons, but are still the same element, we call these variants "isotopes".

Hope it helped,

BiologiaMagister

Two atoms are the same element if they have the same atomic number

Option A

Explanation:

The atomic number of an element is defined as the number of protons or electrons of an element. This signature of sub atomic particles is distinct for each element. No 2 elements have the same atomic number.

Sometimes the properties of elements are attributed towards arrangement and number of protons and electrons of an element. The elements are arranged according to their atomic number in a periodic table.

equal distribution i think.