MASS NUMBER

NUMBER MASS
 Indicates the number of proton and neutrons in the atomic nucleus.
 Proton particles and neutrons as the composer called the atomic nucleus Nucleon.
 nucleon in the number of atomic elements is expressed as a number Mass (given the symbol of the letter A), so that:
A = mass number
= Number of proton (p) + number of neutrons (n)
A = p + n + n = Z
 The single atom with atomic number on the left of the mass and number in the top left of the symbol of the atom. This kind of notation called Nuklida.

Description:
X = = A symbol of atomic mass number
Z = atomic number Example: