Answer
An atom is the smallest particle of a chemical element that can express the unique properties of that element. Atoms have a dense positively charged nucleus(inner core) and a periphery of energy shells with negatively charged electrons. Atoms of the same element have the same number of protons, but the number of neutrons may vary, giving rise to isotopes of the same element with the same number of protons but with a different number of neutrons in their nuclei. Thus an atom of the element Hydrogen always has one proton in its nucleus. But hydrogen atoms may have one, two or zero neutrons. The respective Hydrogen isotopes that result are called Deuterium Tritium and Protium (Hydrogen 1)
Work Step by Step
An atom is the smallest particle of a chemical element that can express all the characteristic properties of the element. Atoms have positively charged nuclei which are usually made up of positively charged protons and an equal number of neutral neutrons. The periphery of atoms have energy levels (shells) which contain characteristic numbers of negatively charged electrons which are usually equal to the number of protons in a stable isotope. The element Hydrogen has three isotopes (Protium, Deuterium, and Tritium) while Oxygen has three stable isotopes, and Carbon has fifteen.
