Question

define atomicity , molecular mass , mass no. no spam plzzz dont copy the ans. frm google otherwise i ll report.........

Answer 1

Atomicity- Atomicity is the number of atoms of an element present in one molecule of that element. 

Molecular mass- The molecular mass of a substance is the sum of the atomic masses of all the atoms present in a molecule of that substance. This is also called the relative molecular mass and its unit is atomic mass unit (u). Hence, to calculate the mass of molecules i.e. to calculate the molecular mass, the mass of all the atoms present in it are added.

Mass number is the sum of number of protons and number of neutrons in an atom.

Mass number = number of protons + number of neutrons

Or

Mass number = atomic number + number of neutrons

Answer 2

Molecular mass or molecular weight is the mass of a molecule. It is calculated as the sum of the atomic weights of each constituent element multiplied by the number of atoms of that element in the molecular formula