Question

The relative atomic mass of hydrogen atom is:
(A) 1
(B) 1.008
(C) 1.08
(D) 1.0008

Answer 1

Hint: Relative atomic mass is an approximate mass of the atom or element with respect to the mass of Carbon-12. Relative atomic mass is also calculated using the relative abundance of the element and its atomic mass.

Complete step by step answer:
A hydrogen atom is the first element in the periodic table with atomic number 1. It is an electrically neutral atom containing a single positively charged proton and a single negative charged electron bound to the nucleus by the coulomb force.
The relative atomic mass of an element is the average mass of its atoms, compared to ${\displaystyle \frac{1}{12}}$th the mass of carbon-12 atoms. The relative atomic mass of an element is calculated from: the mass numbers of its isotopes.
${\displaystyle \frac{1}{12}}$th of carbon-12 is nothing but ${\displaystyle \frac{1}{12}}$ of its mass number (12) =1
And the mass of an atom of hydrogen = $1.6736\times {10}^{-24}g$
Relative atomic mass would then have equal to the mass of an atom of hydrogen itself since the denominator is 1, that is,= $1.67\times {10}^{-24}g$
In terms of amu, 1amu= $1.67\times {10}^{-24}g$,
The mass would be $\to {\displaystyle \frac{1.6736\times {10}^{-24}g}{1.67\times {10}^{-24}g}}=1.0078amu$
Therefore, the value is approximately equal to 1.0080 amu.
Hence, the correct answer is the B option.

Note: It consists of three isotopes namely Protium, deuterium and tritium. The most abundant isotope, hydrogen-1, protium or light hydrogen, contains no neutrons and is simply a proton and an electron. Protium is stable and makes up 99.98% of naturally occurring hydrogen atoms.