Note:
1 A (armstrong) = 10⁻¹⁰ m
1 nm (nanometer) = 10⁻⁹ m
Given:
Radius of a krypton atom = 1.9 A = 1.9 x 10⁻¹⁰ m
Part (a)
[tex]1.9\,A = (1.9\,A)*(10^{-10}\, \frac{m}{A})*( \frac{1}{10^{-8}} \frac{nm}{m}) } =0.019\,nm[/tex]
Answer: 0.019 nm
Part (b)
The diameter of a krypton atom = 2*1.9A = 3.8 A = 3.8 x 10⁻¹⁰ m.
The number of krypton atoms within a length of 1.0 mm is
[tex] \frac{1.0\, mm}{3.8 \time 10^{-10}\, m} = \frac{10^{-3}\, m}{3.8 \times 10^{-10} \,m} =2.632 \times 10^{6}[/tex]
Answer: About 2.632 x 10⁶ atoms
Part (c)
The radius of a krypton atom is
1.9 A = (1.9 x 10⁻¹⁰ m)*(10² cm/m) = 1.9 x 10⁻⁸ cm
The volume of a krypton atm is
[tex] \frac{4 \pi }{3} (1.9 \times 10^{-8} \, cm)^{3} = 2.873 \times 10^{-23} \, cm^{3}[/tex]
Answer: 2.873 x 10⁻²³ cm³
