Definitions and Equations in Atoms and Reactions OCR

Isotopes

Isotopes of an element have the same number of protons and electrons but a different number of neutrons in the nucleus.

Relative atomic mass Ar

The average massof an atom of an element on a scale where an atom of carbon 12 is 12

Relative isotopic mass

the mass on an atom of an isotope of an element when an atom of carbon 12 is 12

Ar = Abundance x(or times) atomic mass

Relative molecular mass or relative formula mass,Mr

is the average mass of a molecule or formula unit on a scale where one atom of carbon 12 is 12

add up all the relative atomic masses of all ions in the formula unit

The mole

1 mole = ~6.02 x 10 to…