Geoffrey has the atoms of an unknown element. His experiment concludes that these atoms are electrically neutral. What is the only thing he can say for certain about the atomic structure of the element with this information?

a
The number of protons and the number of electrons are the same
b
The number of protons and the number of neutrons are the same
c
The atomic number and the atomic mass are the same
d
The object belongs in the period IIVA

a) The number of protons and the number of electrons are the same.

Since the atoms are electrically neutral, this means that the number of protons, which have a positive charge, is equal to the number of electrons, which have a negative charge.

The correct answer is a) The number of protons and the number of electrons are the same.