Question

What is difference between Atom and Element ?

Answer 1

An atom is a electrically neutral structure composed by electrons, protons and neutrons (except in hydrogen with mass number 1).

What we artificially call an element is the group of atoms that share the same atomic number (number of protons) or isotopes.

For example: Hydrogen (an element) can exist in nature in 3 different atoms - isotopes, of course - all with atomic number 1 but with different mass numbers: Z (mass number, number of protons and neutrons) = 1 (with 1 proton in the nucleus, the most common form, stable), Z=2 (with 1 proton and 1 neutron, heavier and less stable, slightly radioactive, also called deuterium), Z=3 (with 1 proton and 2 neutrons, the heaviest and less stable of the three isotopes, radioactive).

As one can see with uranium, the disproportion of protons and neutrons is necessary within certain limits in order to stabilize all the positive charges (protons): U with Z=235 is radioactive while uranium with Z=238 isn't; this tends to happen mostly in heavy elements.

Answer 2

Atom is simply the smallest particle of an Element whereas Element is the purest substance that contain only one type of atom.

Answer 3

An atom is made up of a single particle. An element is a substance containing the same type of atom (many atoms which are the same.)