Question

How many grams does an atom of hydrogen weigh?

Answer 1

Hint :Hydrogen is the first element in the periodic table with atomic number $ \left( 1 \right) $ . Hydrogen is made up of one proton and one electron. Electronic configuration of hydrogen is $ \left( {1{s^2}} \right) $ .Earlier chemists selected the hydrogen atom as the standard substance because it is the lightest atom of all the known atoms.

Complete Step By Step Answer:
Atomic mass of hydrogen is calculated with reference to the standard carbon atom $ \left( {{C^{12}}} \right) $ .
 In order to determine grams of hydrogen first we have to calculate the gram atomic mass of hydrogen.
Gram atomic mass of hydrogen = atomic mass of hydrogen expressed in term of gram
Gram atomic mass of hydrogen = $ \left( x \right)g $
As we know weight of one mole of hydrogen atom is $ 1.008g $
We know that one mole of any element contains atoms equal to Avogadro number $ \left( {6.022 \times {{10}^{24}}} \right) $ .
Therefore, one mole of hydrogen also contains $ 6.022 \times {10^{23}} $ atoms.
Which means that the weight of \[6.022 \times {10^{23}}\] atoms of hydrogen is equal to $ 1.008g $ .
 If weight of $ 6.022 \times {10^{23}} $ atoms $ = 1.008g $ of hydrogen
Hence, weight of $ 1 $ atom $ = \dfrac{{1.008}}{{6.022 \times {{10}^{23}}}} $ $ g $
After solving we get, $ 1 $ atom $ = \dfrac{{0.16736}}{{{{10}^{23}}}} $ $ g $
 $ 1 $ atom $ = 0.16736 \times {10^{ - 23}} $ $ g $
Finally we get the weight of one atom of hydrogen $ 1.6736 \times {10^{ - 24}}g $ .

Note :
Currently $ \left( {{C^{12}}} \right) $ isotope of carbon is used as a standard atom to determine the relative atomic mass of other atoms. Atomic mass is also expressed in terms of amu (atomic mass unit).
 $ 1 $ amu $ = 1.66056 \times {10^{ - 24}}g $ .