Binary Compounds with Chlorine

When an element reacts with chlorine, it can form a binary compound. A binary compound is a compound composed of two different elements. In the given options of K, Ca, Fe, and Zn, we need to determine which element can form more than one binary compound with chlorine.

K (Potassium)
Potassium belongs to Group 1 of the periodic table and has the electronic configuration of 1s2 2s2 2p6 3s2 3p6 4s1. It readily loses one electron to achieve a stable electron configuration. The chloride ion has a -1 charge, so when potassium reacts with chlorine, it forms K+ and Cl- ions, resulting in the binary compound KCl. Since potassium has only one valence electron, it can only form one binary compound with chlorine.

Ca (Calcium)
Calcium belongs to Group 2 of the periodic table and has the electronic configuration of 1s2 2s2 2p6 3s2 3p6 4s2. It loses two electrons to achieve a stable electron configuration. When calcium reacts with chlorine, it forms Ca2+ and Cl- ions, resulting in the binary compound CaCl2. Calcium can only form one binary compound with chlorine.

Fe (Iron)
Iron belongs to Group 8 of the periodic table and has multiple oxidation states. The commonly observed oxidation states of iron are +2 and +3. When iron reacts with chlorine, it can form two binary compounds: FeCl2 and FeCl3. In FeCl2, iron has an oxidation state of +2, while in FeCl3, iron has an oxidation state of +3. Therefore, iron can form more than one binary compound with chlorine.

Zn (Zinc)
Zinc belongs to Group 12 of the periodic table and commonly has a +2 oxidation state. When zinc reacts with chlorine, it forms Zn2+ and Cl- ions, resulting in the binary compound ZnCl2. Zinc can only form one binary compound with chlorine.

Conclusion
Among the given options, Fe (Iron) is the element that can form more than one binary compound with chlorine. It can form FeCl2 and FeCl3, while the other elements (K, Ca, and Zn) can only form one binary compound with chlorine.