What is the difference between atoms elements and the periodic table?

Answer 1

Valence electrons are the electrons on the outermost shell of an atom. Elements on the Periodic Table is the substance. For example titanium is an element, oxogen is an element. The elements on the periodic table are classified by their atomic number. The atomic number is the number of protons in the nucleus of the atom. Also for each element there is the Atomic Mass. The atomic mass is the number of protons plus neutrons. The units for atomic mass is amu (atomic mass units).

Elements in the same column have the same number of valence electrons, so they tend to behave similarly.

Answer 2

The difference between each element on the periodic table is the number of protons in the nucleus. If several atoms have the same amount of protons but a different number of neutrons then they are called isotopes, but they are still the SAME element. For example Hydrogen gas one proton in its nucleus; Deuterium has one proton and one neutron and Tritium has one proton and two neutrons, so they are all still hydrogen in that they have one proton, regardless of the number of neutrons.