Question

Is the electron configuration given below for an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal.
(a) 1s2 2s2 2p6 3s2 3p5
(b) 1s2 2s2 2p6 3s2 3p6 3d7 4s2
(c) 1s2 2s2 2p6 3s2 3p6 3d7 4s2 4p6
(d) 1s2 2s2 2p6 3s2 3p6 3d7 4s1

Answer 1

Answer :

(a) $1s^22s^22p^63s^23p^5$   → Halogen

(b) $1s^22s^22p^63s^23p^63d^74s^2$    → Transition metal

(c) $1s^22s^22p^63s^23p^63d^{10}4s^24p^6$   → Transition metal

(d) $1s^22s^22p^63s^23p^63d^4s^1$   → Transition metal

Explanation :

Inert gas : These are the gases which lie in group 18.

Their general electronic configuration is: $ns^2np^6$ where n is the outermost shell.

Halogen : These are the elements which lie in group 17.

Their general electronic configuration is: $ns^2np^5$ where n is the outermost shell.

An alkali metal : These are the elements which lie in group 1.

Their general electronic configuration is: $ns^1$ where n is the outermost shell.

An alkaline earth metal : These are the elements which lie in group 2.

Their general electronic configuration is: $ns^2$ where n is the outermost shell.

Transition elements : They are the elements which lie between 's' and 'p' block elements. These are the elements which lie in group 3 to 12. The valence electrons of these elements enter d-orbital.

Their general electronic configuration is: $(n-1)d^{1-10}ns^{0-2}$ where n is the outermost shell.

(a) $1s^22s^22p^63s^23p^5$

The element having this electronic configuration belongs to the halogen family.

(b) $1s^22s^22p^63s^23p^63d^74s^2$

The element having this electronic configuration belongs to the transition family.

(c) $1s^22s^22p^63s^23p^63d^{10}4s^24p^6$

The element having this electronic configuration belongs to the transition family.

(d) $1s^22s^22p^63s^23p^63d^4s^1$

The element having this electronic configuration belongs to the transition family.