Question

This chart lists four elements from the periodic table.

Answer 1

Iodine and Calcium is the correct answer

Answer 2

Answer: d. iodine and calcium

Explanation: Ionic bonds are formed by transfer of electrons between metal and non metals.

Covalent bonds are formed by sharing of electrons between non metals

Electronic configuration of calcium:

$[Ca]=[Ar]4s^2$

Calcium atom will lose two electron to gain noble gas configuration and form calcium cation with +2 charge.

$[Ca^{2+}]={Ar]$

Electronic configuration of iodine:

$[I]=[Kr]4d^{10}5s^25p^5$

Iodine atom will gain one electron to gain noble gas configuration and form iodide ion with -1 charge.

$[I^-]=[Kr]4d^{10}5s^25p^6$

In calcium iodide the one electron from calcium metal gets transferred to iodine atom and thus form an ionic bond to give $CaI_2$