If a bromine atom is available in the form of, say two isotopes. Class 9

If a bromine atom is available in the form of, say two isotopes. Class 9

Question 1.

If a bromine atom is available in the form of, say two isotopes, [latex]{ }_{35}^{79} \mathrm{Br}[/latex] (49.7%) and [latex]{ }_{81}^{35} \mathrm{Br}[/latex] (50.3%), calculate the average atomic mass of the bromine atom. (Page 156) Class 9

Answer:

Weighted average atomic mass = (mass of first isotope × its % abundance/100) + (mass of second isotope × its % abundance/100)

= (79 × 49.7/100) + (81 × 50.3/100)

= (79 × 0.497) + (81 × 0.503)

= 39.263 + 40.743

= 80.006 u ≈ 80 u

Answer: The average atomic mass of bromine is approximately 80 u.

What if (Page 147)

Question 1.

What if an atom had no empty space? How would this have affected the size of various objects? Class 9

Answer:

If atoms had no empty space, their size would be much smaller. Since most of the volume of matter is due to empty space in atoms, removing it would make objects extremely small and compact. All substances would shrink drastically in size.