Question

Given that the percentage abundance of isotope 20 Ne is 90% and that of 23 Ne is 10%. Calculate the average atomic mass of Neon

Answer 1

Average atomic mass=(20+23)÷2=43÷2=20.5

Answer 2

Answer: The average atomic mass of neon is 20.3

Solution : Given,

Mass of Neon-20 isotope  = 20

% abundance of Neon-20 isotope = 90%=0.9

Mass of Neon-23 isotope =  23

% abundance of Neon-23 isotope= 10% = 0.1

Formula used for average atomic mass of an element :

$\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}\times {{\text { fractional abundance}})$

$\text{ Average atomic mass of an element}=\sum[(20\times0.9)+(23\times 0.1)$

$\text{ Average atomic mass of an element}=20.3$

Therefore the average atomic mass of an element is 20.3.