Question

the atomic mass of an element is known to be 32,064u. one isotope occurs naturally with an abundance of 95.018% and has atomic mass of 31.971. If there is one other main isotope of this element, what will be its mass number?

Answer 1

Atomic mass of an element is 32.064u.

One isotope has abundance of 95.018% and has atomic mass 31.971u.

The other isotope has abundance of 4.982 and let its atomic mass be x.

Now,

$(95.018×31.971 + x×4.982)/100 = 32.064$

$3037.82048 + 4.982x = 3206.4$

$x=(3206.4-3037.82048)/4.982$

$x=33.8377198(Answer)$

The mass number of other isotope is 33.8377198u