Question

in which of the following groups of ions are the charges all shown correctly?

k2 -, f -, mg2+

na+, i -, rb-

li -, o2 -, s2+

ca2+, al3+, br -

Explanation:

• For \(K\), it is in Group 1 of the periodic table and loses 1 electron to form \(K^{+}\), not \(K^{2 -}\).
• For \(Rb\), it is in Group 1 and loses 1 electron to form \(Rb^{+}\), not \(Rb^{-}\).
• For \(Li\), it is in Group 1 and loses 1 electron to form \(Li^{+}\), not \(Li^{-}\). For \(S\), it gains 2 electrons to form \(S^{2 -}\), not \(S^{2+}\).
• \(Ca\) (Group 2) loses 2 electrons (\(Ca^{2+}\)), \(Al\) (Group 13) loses 3 electrons (\(Al^{3+}\)), and \(Br\) (Group 17) gains 1 electron (\(Br^{-}\)) which are all correct.

Answer:

\(Ca^{2+}, Al^{3+}, Br^{-}\)