Question

what is formula for finding average atomic mass ?explain with an example.(class 9th)

Answer 1

atomic number of the one isotope ×% of atomic isotope + atomic mass of another isotope ×% of another isotope
example here chlorine has 2 isotope & mass of 1 isotope is 35 & other is 37
% of atomic mass is 75% & 25%


here average atomic mass is 35.5u

Answer 2

Average atomic mass of elements,

Let it's one isotope X1 is in a% and other isotope X2 in b%.

Average atomic mass of X
= (Mass of X1 * a% + Mass of X2 * b%) / 100.

Hope it's helpful to u.