Question

A student reported the radius of Cu, $C{u}^{+}andC{u}^{2+}$ as 122 pm, 96 pm and 72 pm. correct order of increase radius

• A. $1>2>3$
• B. $3>2>1$
• C. $2>3>1$
• D. none of these

Answer 1

The correct option is A $1>2>3$

$Cu,C{u}^{+}andC{u}^{2+}$ have same number of protons but different number of electrons. In moving from Cu to $C{u}^{+}toC{u}^{2+},$ the number of electrons decreases thus effective nucelar charge and force of attraction between the nucleus and valence elecron increases and hence size decreases. Thus the correct order is $Cu\left(0.122nm\right)>C{u}^{+}\left(0.096nm\right)>C{u}^{+2}\left(0.072nm\right).$