Question

Write the electronic configuration of atoms of:
(a) Potassium (K) (b) Lithium (Li) (c) Fluorine (F) (d) Chlorine (Cl)
Use these electronic configuration to explain why Potassium is more reactive than Lithium and
Fluorine more reactive than Chlorine?

Answer 1

Electronic configuration of :
1) Potassium (K) = The atomic number is 19. Its electronic configuration is (2,8,8,1).
2) Lithium (Li) = The atomic number is 3. Its electronic configuration is (2,1) .
3) Fluorine (F) = The atomic number of fluorine is 9. Its electronic configuration is (2,7).
4) Chlorine (Cl) = The atomic number of chlorine is 17. Its electronic configuration is (2,8,7) .

Potassium and Lithium are metals and they have the tendency to loose electrons.Lithium is smaller in size than potassium . so valence electrons are more tightly held in Li than K. Due to larger size of K the valence electrons are loosely held and easy to remove the electron from K.Hence K is more reactive.
Fluorine and Chlorine are non-metals.They have the tendency to gain electron. Due to smaller size of fluorine it can hold the incoming electron more tightly than Cl hence more reactive than Cl.