Which of the following elements has maximum number of unpaired electrons?PotassiumPhosphorusChlorineArgon

To answer this question, we need to look at the electron configurations of each of these elements.

1. Potassium (K) has an atomic number of 19. Its electron configuration is [Ar] 4s1. This means it has 1 unpaired electron in the 4s orbital.

2. Phosphorus (P) has an atomic number of 15. Its electron configuration is [Ne] 3s2 3p3. This means it has 3 unpaired electrons in the 3p orbital.

3. Chlorine (Cl) has an atomic number of 17. Its electron configuration is [Ne] 3s2 3p5. This means it has 1 unpaired electron in the 3p orbital.

4. Argon (Ar) has an atomic number of 18. Its electron configuration is [Ne] 3s2 3p6. This means it has no unpaired electrons as all its orbitals are fully filled.

Therefore, among Potassium, Phosphorus, Chlorine, and Argon, Phosphorus has the maximum number of unpaired electrons.