The number of gram atoms present in $10$ g of $CaC{O}_3$ is:

The correct option is B $0.5$
The molar weight of calcium carbonate is $100$ g/mol.

Therefore, $10$ g is equal to $0.1$ mole.

$1$ mole of calcium carbonate contains $5$ moles of atoms.

Hence, $10$ g of calcium carbonate contains $0.5$ gram atoms.