what relationship exists between the atomic number of an element and the number of protons in a neutral atom of an element?​

Neutral atoms of an element contain an equal number of protons and electrons. The number of protons determines an element's atomic number (Z) and distinguishes one element from another. For example, carbon's atomic number (Z) is 6 because it has 6 protons.

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).