Answer
See the explanation
Work Step by Step
Arranging the atoms and/or ions in order of decreasing size:
a) O, O^-, O^2-
Explanation:
The size of an atom or ion increases as the number of electrons increases and the nuclear charge remains the same or decreases.
O (8 electrons) < O^- (9 electrons) < O^2- (10 electrons)
Therefore, the order from largest to smallest is: O^2-, O^-, O.
b) Fe^2+, Ni^2+, Zn^2+
Explanation:
The size of a cation decreases as the nuclear charge increases while the number of electrons remains the same.
Fe^2+ (26 protons) > Ni^2+ (28 protons) > Zn^2+ (30 protons)
Therefore, the order from largest to smallest is: Fe^2+, Ni^2+, Zn^2+.
c) Ca^2+, K+, Cl-
Explanation:
The size of an ion increases as the number of electrons increases and the nuclear charge remains the same or decreases.
Ca^2+ (20 protons, 18 electrons) < K+ (19 protons, 18 electrons) < Cl- (17 protons, 18 electrons)
Therefore, the order from largest to smallest is: Cl-, K+, Ca^2+.
