Question

A $124g$ of ${{P}_{4}}$ will contain which of the following?
a.$4$ atoms of Phosphorus
b.$4{{N}_{A}}$ atoms of Phosphorus
c.${{N}_{A}}$ atoms of Phosphorus
d.1 molecule of Phosphorus
1.a and d
2.b and c
3.a and c
4.b and d

Answer 1

Molar mass in grams of any element or a compound is equal to its molecular mass in an atomic mass unit. One mole of any element or a compound is equal to $6.022\times {{10}^{23}}$ molecules.

Complete step by step answer:
Mass number of Phosphorus element$P=31u$
Molecular mass of ${{P}_{4}}=124u$
Thus, molar mass of ${{P}_{4}}=124g$
Thus, $124g$ of ${{P}_{4}}$ contains $6.022\times {{10}^{23}}$ molecules, which is equal to Avogadro Constant, ${{N}_{A}}$.
Which leads to the conclusion that c) is correct.
Now the $1$ molecule of ${{P}_{4}}$ contains $4$ atoms of $P$.
Thus,$124g$ of ${{P}_{4}}$ contains $4{{N}_{A}}$ atoms of Phosphorus.
Which leads to the conclusion that b) is correct.
Hence, options b) and c) are correct.

So, option 2 is correct.

Additional Information:
1 mole of a molecule contains$6.022\times {{10}^{23}}$ molecules, this number is known as Avogadro Constant, ${{N}_{A}}$
This is known as mole concept. Molar mass in grams is equal to molecular mass in atomic mass units.

Note:
Mass number of an element is the sum of the number of protons and neutrons in the atom’s nucleus. Phosphorus has$15$ protons and $16$ neutrons hence its mass number is $15+16=31u$.