Which is the correct oxidation state of lead?

Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements.
$(a)$ Lithium and oxygen
$(b)$ Magnesium and nitrogen
$(c)$ Aluminium and iodine
$(d)$ Silicon and oxygen
$(e)$ Phosphorus and fluorine
$(f)$ Element $71$ and fluorine

What is the oxidation state of chlorine in its weakest oxoacid?

Which is true for an element $R$ present in $III$ group of the periodic table?

In the transition of $Zn$ atoms to $Zn^{2+}$ ions,there is a decrease in the

The group number,number of valence electrons,and valency of an element with atomic number $15$,respectively,are