Atomic mass of boron is 10-81- It has two isotopes namely - -11-5B- and - -x-5 B- nbsp-with their relative abundance of 80

The correct option is B 10We have, #160;Average atomic mass = #160;(mass× percentage abundance of 1 )+ (mass× percentage abundance of 2) 100 10.81 # ...

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Atomic mass o...

Question

Atomic mass of boron is 10.81. It has two isotopes namely $_{5}^{11} B$ and $_{5}^{x} B$ with their relative abundance of 80% and 20% respectively. The value of x is:

10.05

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10.01

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10.02

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Solution

The correct option is B 10
We have,
Average atomic mass $= \frac{(m a s s \times p e r c e n t a g e a b u n d a n c e o f 1) + (m a s s \times p e r c e n t a g e a b u n d a n c e o f 2)}{100}$

10.81 $= \frac{(11 \times 80) + (x \times 20)}{100}$

$x = 10.05 \approx 10$ (since mass number is a whole number)

Hence, the correct option is $(B)$ .

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Atomic mass of boron is 10.81. It has two isotopes namely 115B and x5B with their relative abundance of 80% and 20% respectively. The value of x is:

The correct option is B 10We have, Average atomic mass =(mass× percentage abundance of 1)+(mass× percentage abundance of 2)10010.81 =(11×80)+(x×20)100x=10.05≈10 (since mass number is a whole number)Hence, the correct option is (B).

Atomic mass of boron is 10.81. It has two isotopes namely $_{5}^{11} B$ and $_{5}^{x} B$ with their relative abundance of 80% and 20% respectively. The value of x is: