Question

Explain the trend in ionic size of first row elements of transition series.

Answer 1

i. As the oxidation state increases, ionic radii decreases due to increase in effective nuclear charge. 

ii. For a given oxidation state, as the nuclear charge increases, the ionic radii decreases. 

eg. With increase in the effective nuclear charge, the ionic radii decreases gradually from Ti²⁺ to Cu²⁺.

iii. In a given period, transition elements have small ionic radii than representative elements.

Note: The trend in ionic radii is illustrated by the following table.

Element		Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn
Ionic radii in pm	M2+	-	90	88	84	80	76	76	72	72	74
	M3+	81	76	74	69	66	64	63	-	-	-