Question

question 3
what determines the identity of an element?
the size of the atom
the number of neutrons
the number of protons
the number of electrons
question 4
why do electrons orbit the nucleus instead of staying still?
they are always in motion due to their charge and energy.
they are too large to stay inside the nucleus.

Explanation:

The number of protons in an atom's nucleus is called the atomic number. Each element has a unique atomic number. For example, hydrogen has 1 proton (atomic number 1), helium has 2 protons (atomic number 2), etc. So, the number of protons determines the identity of an element. Electrons are in motion due to their charge (negative charge, while the nucleus has positive charge from protons) and the energy they possess, which makes them orbit the nucleus rather than stay still.

Answer:

For Question 3: The number of protons.
For Question 4: They are always in motion due to their charge and energy.