Question

Mass of single atom of $X$ is $2.65\times {10}^{-23}g.$ $X$ should be:

• A. ${}^{12}C$
• B. ${}^{14}N$
• C. ${}^{16}O$
• D. ${}^{1}H$

Answer 1

Answer: (C)

${}^{16}O$

Mass of single atom of $x=2.65\times {10}^{-23}g$

In $1$ mole, $6.022\times {10}^{23}$ atoms are present

$\therefore$ Mass of $1$ mole $=6.022\times {10}^{23}\times 2.65\times {10}^{-23}$

$=15.96g$

$\approx 16g$

But mass of $1$ mole of $O$ is $16g$

$\therefore X$ should be ${}^{16}O$.