# Gram Atom

The term gram-molecule (g mol) was formerly used for 'mole of molecules', and gram-atom (g atom) for 'mole of atoms'. For example, 1 mole of MgBr 2 is 1 gram-molecule of. Gram Atom the number of grams of a chemical element equal to its atomic weight. Thus, for example, for hydrogen (atomic weight 1.00797) the gram atom is 1.00797 g. The term gram-atom (abbreviated gat.) has been used for a related but distinct concept, namely a quantity of a substance that contains Avogadro's number of atoms, whether isolated or combined in molecules. Thus, for example, 1 mole of M g B X 2 is 1 gram-molecule of M g. Concept of one gram atom: One gram atom of an element is the amount of the element which is equal to the mass of 1 mole (or 6.023 × 10 23 atoms) of the element or atomic mass of the element in grams. Thus one gram atom of sodium is equal to one mole of sodium corresponds to 23 grams of sodium, because the atomic mass of sodium is 23 grams.

### What is the mass of one atom of magnesium in grams?

#### Explanation: Here are some prefined values. m = mass = $' g '$
M = molar mass = $' g \frac{'}{' m o l '}$
A = Avagadro's Constant = $\frac{6.02214086 \cdot {10}^{23} ' p a r t i c \le s '}{'} m o l '$

$' m a s s \frac{'}{'} p a r t i c \le ' = ' M \left(M g\right) \frac{'}{'} A '$, the particle being the one atom, so the mass for one atom.

$m \left(M g\right) = ' M \left(M g\right) \frac{'}{'} A ' = \frac{24.305 ' g \frac{'}{'} m o l '}{6.02214086 \cdot {10}^{23} ' p a r t i c \le \frac{'}{'} m o l '} = 4.03594014 \cdot {10}^{-} 23 ' g \frac{'}{'} p a r t i c \le '$

## Gram Atom

So $4.03594014 \cdot {10}^{-} 23 ' g r a m s '$ is the mass per particle, the particle being an atom.