Question

One atom of an element weighs $3.98\times {10}^{-23}g.$ Its atomic weight is:

• A. 18
• B. 29.9
• C. 24
• D. 108

Answer 1

The correct option is C 24

The mass of one atom of an element,

$A=3.98\times {10}^{-23}g$

We know, $1$ mole of an atom is $6.023\times {10}^{23}$ atoms.

$1$ mole of an atom $=$ its atomic weight

$\therefore$ Atomic weight of element $A=3.98\times {10}^{-23}\times 6.023\times {10}^{23}=23.97g\approx 24g$