Question

the atomic number of each element indicates how many ______ and ______ it contains.
a electrons and protons
b electrons and neutrons
c none of these
d neutrons and protons

Explanation:

The atomic number of an element is defined as the number of protons in the nucleus of an atom of that element. In a neutral atom (which is the most common state in many contexts when referring to atomic number in basic definitions), the number of electrons is equal to the number of protons. Neutrons are not related to the atomic number; the mass number (protons + neutrons) is related to neutrons. So the atomic number indicates the number of electrons (in neutral atom) and protons.

Answer:

A. electrons and protons