Question

ion whose first ionization potential is the highest among the following isoelectronic ions. and why?
Ca2+
Cl-
K+
S2-​

Answer 1

Cl- has higher ionisation potential (IP).

Ionisation potential is the energy required to remove an electron from the valence shell of an isolated gaseous atom.

It increases down a group and decreases across a period. Since metals easily loss electrons, they have low IP.

Answer 2

Answer:

cl- is the answer please mark as brainlist answer