Question

What is the average atomic mass for neon by using below data?
(a) $ Neon-20 $ has a mass of $ 19.9924\text{ }amu. $
(b) $ Neon-21 $ has a mass of $ 20.9940\text{ }amu. $
(c) $ Neon-22 $ has a mass of $ 21.9914\text{ }amu. $
The relative abundance of $ 20Ne $ is $ 90.92% $ and $ 21\text{ }Ne $ is $ .257% $ and $ 22\text{ }Ne $ is $ 8.82%. $ .

Answer 1

Hint :We know that the isotopes can be basically explained as atoms having the same atomic number, but different atomic mass number. This means that the number of protons and electrons in the given atoms are the same, but they differ in the number of neutrons present in them.

Complete Step By Step Answer:
Try to recall that the average atomic mass of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance. Now, by using this you can easily calculate the average atomic mass of neon.

It is known to you that the average mass of an atom of a given element, based on the occurrence and mass of the various isotopes as they are found in the crust and atmosphere. An element does not have an absolute atomic mass. The atomic mass is average because it is calculated on the basis of $ \% $ of the isotopes present in nature.

The solution that was found to this problem is that we take the sum of abundances of each isotope and multiply it with their corresponding atomic mass numbers. This gives us a generalized average value that can be justified for the existence of all the isotopes of the element.

The element under consideration is Neon. Neon has two isotopes namely, $ N{{e}^{20}},N{{e}^{21}} $ and $ N{{e}^{22}}. $ The average atomic mass can be calculated as:
 $ N{{e}_{Average\;atomic\;mass}}=[ 19.9924( 90.92 \% )] + [ 20.9940( 0.257 \% )]+[ 21.9914( 8.82 \% )]amu$
 $ \Rightarrow N{{e}_{Average\text{ }atomic\text{ }mass}}=20.1797amu $

Note :
It should be remembered to you that neon is used for making high-voltage indicators and switching gear, lasers, etc. Also, liquid neon is used as the cryogenic refrigerant. Also, you should be remembered that neon is used in beacon light as a safety signal for air navigators because its light has fog penetration power.