Which of the following particles does not have the same electron configuration as the others?

A. K+
B. Ar
C. Cl^1-
D. Al^3+

D. Al^3+

Explanation:

All the other elements given have the same number of elecetron

K has 19 electrons, since it is given as K+, it means that K has lost one electon, therefore K has 18 electrons now

Cl has 17 electrond, since it is given Cl^1- it means Cl has gained one electron , therefore now Cl has 18 electrons

Ar normally has 18 electrons

Al has 13 electrons, since it is given has Al^3+ it means Al has lost 3 electons, therefore now Al has only 10 electrons

In oder to answer this question easily it is must to know first 20 elements of the Modern Peroidic Table