Question

The distance between adjacent, oppositely charged ions in rubidium chloride is 3.285 Å; in potassium chloride is 3.139Å; in sodium bromide is 2.981 Å and in potassium bromide is 3.293 Å. The distance between adjacent oppositely charged ions in rubidium bromide is

• A. 3.147 Å
• B. 3.385 Å
• C. 3.393 Å
• D. 3.439 Å

Answer 1

Answer: (D)

3.439 Å

Answer 2

$\left( r_{Rb^{+}} + r_{Cl^{-}} \right) + \left( r_{K^{+}} + r_{Br^{-}} \right) - \left( r_{K^{+}} + r_{Cl^{-}} \right) = \left( r_{Rb^{+}} + r_{Br^{-}} \right)$

3.285 + 3.293 – 3.139 = 3.439.