Question

What one characteristic of an atom determines what type of element it is?

the number of neutrons.
the number of protons.
the mass number.
the atomic mass.

Answer 1

the number of protons. hope this helps. :)

Answer 2

the number of protons.

Step-by-step explanation:

The number of protons is also the atomic number that the element has in the periodic table, no element has the same number of protons than any other, and if an atom changes the number of protons in its nucleus it changes the element it is. This gives the atom its characteristics, and its position in the periodic table, this also dictates the type of element that that atom is.