Question

1 atom of an element weighs 1.792x10-22 g. The
atomic weight of element is?
(1) 107.92
(2) 17.92
(3) 1.192
(4) 64​

Answer 1

1 atom of an element weighs 1.792 x 10-²² g. The atomic weight of element is ...

(1) 107.92

(2) 17.92

(3) 1.192

(4) 64

answer : option (1) 107.92g

solution : given, mass of 1atom of an element = 1.792 × 10^-22 g

we know, atomic weight of an element is mass of one mole of atoms of that element.

so, atomic weight = one mole of atoms × mass of an atom

[ one mole of atoms = 6.022 × 10²² atoms]

= 6.023 × 10²³ × 1.792 × 10^-22 g

= 10.791424 × 10 g

= 107.91424 ≈ 107.92 g

atomic weight of element is 107.92g