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JEE Main 202118 MarchMorning Shift

Exam: JEE Main
Year: 2021
Date: 18 March
Shift: Morning Shift
Subject: Chemistry
Chapter: Classification of Elements and Periodicity in Properties

JEE Main 2021 · 18 March · Morning Shift · Chemistry · Classification of Elements and Periodicity in Properties

The ionic radius of Na ^ + ions is 1 . 02 ° A . The ionic radii (in...

The ionic radius of

{Na}^{+}

ions is

1 . 02\overset{°}{A} .

The ionic radii (in

\overset{°}{A}

)

of {Mg}^{2 +}

and

{Al}^{3 +},

respectively, are

Options

A $1 . 05$ and $0 . 99$
B $0 . 72$ and $0 . 54$
C $0 . 85$ and $0 . 99$
D $0 . 68$ and $0 . 72$

Correct answer

B. $0 . 72$ and $0 . 54$

Step-by-step solution

As we know nuclear charge increases, attraction of nucleus on electron increases because of that size decreases.

Here all ions have same number of electrons so as the number of protons increases nuclear charge increases and size decreases.

The ionic radii order is ${Na}^{+} > {Mg}^{2 +} > {Al}^{3 +}$

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