Which of the following pair of substances can
be used to prepare copper(ii) nitrate in the
laboratory?

a) copper(ii) oxide and nitric acid

b) copper(ii) sulphate and nitric acid

c) copper(ii) chloride and potassium nitrate

d)copper(ii) carbonate and ammonium
nitrate

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.