Question

Correct arrangement of the following species in the increasing order of their size is?

Answer 1

Answer: see the explanation :-

Explanation :- more positive charge means more protons than electrons.

due to more proton they will attract the electrons strongly so size decrease.

conclusion is that more positive charge will have more smaller size.

hence option [ A] is correct

Answer 2

EXPLANATION.

$\sf \to \: elements \: are \: = n {}^{3 - },o {}^{2 - } ,f {}^{ - } ,na {}^{ + } ,mg {}^{2 + } ,al {}^{3 + }$

it is an isoelectronic species.

in isoelectronic species as negative charge is

increase the size of element increase.

in isoelectronic species as positive charge

is increase the size of element decrease.

Therefore,

$\sf \to \: al {}^{3 + } \: has \: more \: positive \: charge \: so \: it \: is \: smaller \: in \: size \\ \\ \sf \to \: order \: of \: increases \: order \: of \: size \\ \\ \sf \to \: al {}^{3 + } ,mg {}^{2 + } ,na {}^{ + } ,f {}^{ - } ,o {}^{2 - } ,n {}^{3 - } \\ \\ \sf \to \: option \: (1) \: is \: correct \:$