Chemistry Classification of Elements and Periodicity in Properties

O^-2 & Mg⁺² are isoelectronic with Al⁺³

Ionization enthalpy: B < Be < O < N

IE of N > O [Due to half-filled configuration]

IE of Be > B [Due to penetration effect]

Ionic radius of isoelectronic species depends upon $\frac{Z}{e}$ $\frac{}{}$ ratio; Hence Ionic radius of $O^{--}>$ ${}^{}$ ionic radius of Mg+

Ionisation enthalpy order :

              Li > Na > K

              He > Ne > Ar > Kr > Xe > Rn

              Sr > Rb

              Zn > Ga

Rb and Cs has nearly same ${\Delta }_{e.g}H=-46kJ/mole$ ${}_{}$

Ar and Kr has same ${\Delta }_{e.g.}H=+96kJ/mole$ ${}_{}$

Au + NaCN + O₂ → Na [Au (CN)₂]

$Zn+Na\left[Au{\left(CN\right)}_2\right]\to N{a}_2\left[Zn{\left(CN\right)}_4\right]+Au$

$Ais{\left[Au{\left(CN\right)}_2\right]}^{-}andBis{\left[Zn{\left(CN\right)}_4\right]}^{-2}$

Species =CH4 ${}_{}^{}$ $N{H}_4^{+}$ $B{H}_4^{?}$ ${}_{}^{}$

Electrons =101010

Geometry of SF₄ is trigonal bipyramidal, in which there is one lonepair which occupy equatorial position as,

There are two lone pair – bond pair repulsions at 90°

For isoelectronic species

$Ionicradii\propto \frac{Numberofe}{Numberofp}$              

$\begin{array}{l}N{a}^{+}M{g}^{2+}{N}^{3-}{O}^{2-}{F}^{-}\\ e=1010101010\\ p=1112789\end{array}$                

Hence, correct order of ionic radii is;

$M{g}^{2+}<N{a}^{+}<F^{-}<O^{2-}<N^{3-}$