
InstroTek
48
The atom is not solid, it is mostly space. If the nucleus of
hydrogen was the size of a marble and placed on the 50 yard
line of a football stadium the electron would be the size a
pinhead in the stands.
Each element/atom has been assigned a one or two letter
symbol that is an abbreviation of its name (generally Latin).
Symbol
Latin
English
Au
Aurum
Gold
Cu
Cuprum
Copper
Fe
Ferrum
Iron
The atomic number (Z) is the number of protons in the nucleus
The mass number (A) is the sum of the protons and the neutrons
in the nucleus.
Isotopes
Elements that have the same number of protons (same atomic
Number), but different numbers of neutrons (different atomic
mass numbers) are called Isotopes. Hydrogen has three
isotopes. The most abundant hydrogen isotope has one proton
and no neutrons. The isotope of hydrogen with two neutrons is
called Tritium and is unstable. Tritium is produced in the
atmosphere by neutron bombardment of nitrogen.