Question

the number of in an atoms nucleus is equal to its atomic number.

Explanation:

In atomic structure, the atomic number of an element is defined as the number of protons present in the nucleus of its atom. Protons are positively charged particles located in the nucleus, and this number determines the element's identity. Neutrons are also in the nucleus but their number relates to isotopes, and electrons are outside the nucleus. So the correct term to fill in the blank is protons.

Answer:

protons