Silicon exhibits 4 coordination number in its compound.

Bond energy of F₂ is less than Cl₂.

Mn(III) oxidation state is more stable than Mn(II) in aqueous state.

Elements of 15^th group shows only + 3 and +5 oxidation states.

NH₃ < PH₃ < AsH₃ $$-$$ acidic

Li < Be < B < C $$-$$ 1^st IP

Al₂O₃ < MgO < Na₂O < K₂O $$-$$ basic

Li⁺ < Na⁺ < K⁺ < Cs⁺ $$-$$ ionic radius.

$$\left( {n - 2} \right){f^{1 - 14}}\,\left( {n - 1} \right){s^2}{p^6}{d^{0 - 1}}\,n{s^2}$$

$$\left( {n - 2} \right){f^{0 - 14}}\,\left( {n - 1} \right){d^{0 - 1}}\,n{s^2}$$

$$\left( {n - 2} \right){f^{0 - 14}}\,\left( {n - 1} \right){d^{10}}\,n{s^2}$$

$$\left( {n - 2} \right){d^{0 - 1}}\left( {n - 1} \right)\,{f^{1 - 14}}\,n{s^2}$$

Cr

Fe

Mn

V