Question

What do the numbers listed for an element on the periodic table represent?

Answer 1

The answer is The number with a higher value is the mass, and the number with a lower value is the number of protons. 

The number with a higher value is the mass. This is because the mass number of the element is the sum of the number of protons and number of neutrons in the nucleus of the atom. On the other hand, the number with a lower value is the number of protons. The number of proton in the nucleus of the atom is the atomic number of the element. It involves only numbers of protons, thus, it has the lower value than the mass number.
For example, hydrogen has 1 proton and 1 neutron. Its atomic number is 1 (= number of protons). Its mass number is 2 (1 proton + 1 neutron = 2). Thus, mass number has higher value than the atomic number.