KCET 2025 Chemistry Paper

The electronic configurations of elements X and Y are as follows:
‌X:1s22s22p63s23p3
‌Y:1s22s22p63s23p5
For element X, the configuration corresponds to phosphorus (P), which is in group 15 of the periodic table. For element Y, the configuration corresponds to chlorine (CI), which is in group 17.
Phosphorus (P) has a valency of 3 or 5 .
Chlorine (Cl) has a valency of 1 .
Given these valencies, possible compounds could form:
PCl3, where phosphorus uses its valency of 3 to bond with three chlorine atoms.
PCl5, where phosphorus uses an expanded valency of 5 to bond with five chlorine atoms.
Both PCl3 and PCl5 are covalent compounds. In both scenarios, sharing of electrons occurs between phosphorus and chlorine atoms, resulting in covalent bonds.