gneet

Question
Q132) An element, X has the following isotopic composition ^{200}X : 90% ; ^{199}X : 8%; ^{202}X : 2.0%.

The weighted average atomic mass of the naturally occurring element X is closest to

The weighted average atomic mass of the naturally occurring element X is closest to

SOLUTION

Using formula for average atomic mass

Average mass=(200×90+199×8+202×2)/100

On calculating we get Average atomic mass = 199.08 ≈ 199amu

Answer : (c)