Question

There are three naturally occurring isotopes of neon: neon-20, mass 19.9924 amu, abundance 90.84% neon-21, mass 20.9940 amu, abundance 0.260% neon-22 mass 21.9914 amu, abundance 8.90% What is the atomic mass of neon to 2 sig fig

Answer 1

Molar mass Ne = 20 amu

Step-by-step explanation:

The atomic mass of an atom is defined as the sum of the mases of the isotopes times their abundance. For Neon, the atomic mass is obtained as follows:

Molar mass Ne = 19.9924amu*0.9084 + 20.9940amu*0.00260 + 21.9914amu*0.0890

Molar mass Ne = 20 amu