Question

Which one of the following will have the largest number of atoms?

(A) 1g Fe (at mass of Fe = 56)

(C) 1g Li (at mass of Li = 7)

(B) 1g Na (at mass of Na =23)

(D) 1g F₂ (at mass of F = 19)​

Answer 1

(B) One gram of lithium contains the largest number of atoms.

Explanation:

$\[{\rm{no}}{\rm{. of moles = }}\frac{{{\rm{wt}}{\rm{.}}}}{{{\rm{at}}{\rm{.wt}}{\rm{.or mol}}{\rm{.wt}}}}\]$

One mole contains $\[6.022 \times {10^{23}}{\rm{molecules}}\]$ or atoms.

(A)

$\[{\rm{1gm Fe = }}\frac{1}{{56}} \times 6.022 \times {10^{23}}atoms\]$

$\[{\rm{1gm Fe = 1}}{\rm{.07}} \times {10^{22}}{\rm{atoms}}\]$

(B)

$\[{\rm{1gm Li = }}\frac{1}{7} \times 6.022 \times {10^{23}}atoms\]$

$\[{\rm{1gm Li = 8}}{\rm{.6}} \times {10^{22}}{\rm{atoms}}\]$

(C)

$\[{\rm{1gm Na = }}\frac{1}{{23}} \times 6.022 \times {10^{23}}atoms\]$

$\[{\rm{1gm Na = 2}}{\rm{.6}} \times {10^{22}}{\rm{atoms}}\]$

(D)

$\[{\rm{1gm }}{{\rm{F}}_2}{\rm{ = }}\frac{1}{{19}} \times 6.022 \times {10^{23}}{\rm{molecules}}\]$

$\[{\rm{1gm }}{{\rm{F}}_2}{\rm{ = }}\frac{2}{{19}} \times 6.022 \times {10^{23}}{\rm{atoms}}\]$

$\[{\rm{1gm }}{{\rm{F}}_2}{\rm{ = }}6.3 \times {10^{22}}{\rm{atoms}}\]$