The atomic number is equal to the number of:

Question 1 options:

protons in the nucleus of an atom of that element.

times the atom orbits the Earth

electrons

The atomic number is equal to the atomic weight.

The answer to your question is protons in the nucleus of an atom of that element.

Explanation:

The number of protons in an atom is called atomic number.

a) The first option is correct because it considers the number of protons in an atom as the atomic number.

b) Atomic number and the orbits an atom turns around the earth are independent.

c) Sometimes the number of protons and electrons is equal but as electrons are lost or gained during bonding, electrons are not considered in the definition of atomic number.

d) This definition is wrong, atomic weight is the number of protons plus the number of neutrons in an atom and the atomic number is only the number of protons.