Question

1 amu is equal to $1.66 \times 10^{-24}$ g.
A. True
B. False

Answer 1

Hint: Most of the mass of an atom is constituted by the proton (mass=\[1.672\text{ }\times \text{ }{{10}^{-24}}g\]) and neutron (mass=\[1.674\text{ }\times \text{ }{{10}^{-24}}g\]) present in the nucleus of an atom.

Complete step-by-step answer:

We know that the standard unit of atomic mass has been 1/12th the mass of an atom of the isotope carbon 12.
So according to the above mentioned definition, we can say that
\[Mass\text{ }of\text{ }1\text{ }atom\text{ }=\text{ }12\text{ }amu\]
\[1\text{ }amu\text{ }=\text{ }\left( Mass\text{ }of\text{ }{{1}^{12}}{{C}_{6}}atom \right)/12\]
\[1\text{ }amu\text{ }=\text{ }\left( 1.994\text{ }×\text{ }{{10}^{-23}} \right)/12\]
\[1\text{ }amu\text{ }=\text{ }1.662\text{ }\times \text{ }{{10}^{-24}}g\text{ }or\text{ }1.662\text{ }\times \text{ }{{10}^{-27}}kg\].
Thus we can conclude that 1 amu is equal to \[1.66\text{ }\times \text{ }{{10}^{-24}}g\].
So the correct answer is Option A.

Additional Information:
1. Isotopes are variance of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different number of neutrons in each atom.

2. Carbon-12 is the most abundant of the two stable isotopes of carbon, amounting to 98.93% of the element carbon. Its abundance is due to the triple alpha process by which it is created in stars.

3. Another isotope of carbon that is found is carbon-14, which is radioactive, and is used in radiocarbon dating and radio labelling.

Note: The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit or amu. It is expressed in Daltons. The atomic mass is the weighted average of all the isotopes of that element in which the mass of each isotope is multiplied by the abundance of that particular isotope.