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Boron naturally occurs as a mixture of b...

Boron naturally occurs as a mixture of boron-10 (5 protons + 5 neutrons) and boron-11 (5 protons + 6 neutrons) isotopes. The percentage abundance of B-10 is 20 and that of B-11 is 80. Then, the atomic mass of boron is calculated as follows:

Text Solution

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Atomic mass of
boron `= (10 xx (20)/(100)) + (11 xx (80)/(100))`
`= (10 xx 0.20) + (11 xx 0.80) = 2 + 8.8 = 10.8` amu
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