Question

The weight of one hydrogen atom is:
A. $1.66\times {{10}^{-27}}kg$
B. $2.66\times {{10}^{-27}}kg$
C. $1.76\times {{10}^{-27}}kg$
D. $1.66\times {{10}^{-37}}kg$

Answer 1

Hint: Atomic mass is known as the number of protons and neutrons in an atom, in which each proton and neutron has a mass of around 1 amu (respectively 1,0073 and 1,0087). The electrons inside an atom are so miniscule that their mass is small relative to protons and neutrons. Atomic mass unit is represented by ‘amu’. It is equal to the quantity 1/12th mass of an atom of C-12.

Complete answer:
Atomic mass of an element can be defined as the number which indicates how many times the mass of one atom of the element is heavier in compared to 1/12th of the mass of one of the carbon-12 atoms.
For an element the Atomic mass = mass of one element atom / (1/12th) portion of the mass of one carbon atom.
Unit of atomic mass is represented by 'amu'. It is equal to the quantity 1/12th mass of an atom of C-12.
Actual mass of one atom of C–12 = $1.9924\times {{10}^{-23}}gm$= $1.9924\times {{10}^{-26}}kg$.
1 amu = $1.9924\times {{10}^{-23}}$/ 12 = $1.66\times {{10}^{-24}}kg$ = $1.66\times {{10}^{-27}}kg$.
Atomic mass of an element = mass of one atom of the element / 1 amu.
Atomic mass of an element = atomic mass of an element in amu 1.66 × 10-27 kg
Hence, weight of one hydrogen atom is = 1 amu = 1$\times $ $1.66\times {{10}^{-27}}kg$
 = $1.66\times {{10}^{-27}}kg$

Hence, option A is the correct answer.

Note:
Gram atomic mass (weight) of an element is the mass of Avogadro number $(6.023\times {{10}^{23}})$ of atoms of that element in grams.
Always remember, Atomic mass of an element = mass of one atom of the element / (1/12th) part of the mass of one atom of carbon.
Atomic mass of a hydrogen atom is 1.