Which amongst the following has a greater number of atoms,$11.5 \, g$ of sodium $(Na)$ or $15 \, g$ of calcium $(Ca)$? How? (Given: atomic mass of $Na = 23 \, u$,$Ca = 40 \, u$)

(A) $1$. Calculate the number of atoms in $11.5 \, g$ of $Na$:
- Molar mass of $Na = 23 \, g/mol$.
- Number of moles of $Na = \frac{11.5 \, g}{23 \, g/mol} = 0.5 \, mol$.
- Number of atoms in $Na = 0.5 \times 6.022 \times 10^{23} = 3.011 \times 10^{23}$ atoms.
$2$. Calculate the number of atoms in $15 \, g$ of $Ca$:
- Molar mass of $Ca = 40 \, g/mol$.
- Number of moles of $Ca = \frac{15 \, g}{40 \, g/mol} = 0.375 \, mol$.
- Number of atoms in $Ca = 0.375 \times 6.022 \times 10^{23} = 2.258 \times 10^{23}$ atoms.
$3$. Conclusion:
- Since $3.011 \times 10^{23} > 2.258 \times 10^{23}$,$11.5 \, g$ of sodium contains a greater number of atoms.