Classify an element having the following ground state electron configuration as an alkali metal, alkaline earth metal, nonmetal, halogen, transition metal, or noble gas.

a. [Ne]3s1

b. [Ne]3s23p3

c. [Ar]4s23d104p5

d. [Kr]5s24d1

e. [Kr]5s24d105p6

Alkali metal refers to group1 elements.

Alkali earth metal refers to group 2 elements.

Non metals refers to elements in grouos 4 to group 7.

Halogen refers to group 17 elements

Transition Metal refers to group 3 to group 12 elements

Noble gases refer to elements in group 18.

To obtain the group number from the electronic configuration, we calculate the total number of electrons in the principal quantum number (coefficient of the letters).

a. [Ne]3s1

Principal quantum number = 3

Number of electrons present = 1

This element belongs to group 1. It is an Alkali Metal.

b. [Ne]3s23p3

Principal quantum number = 3

Number of electrons present = 2 + 3 = 5

This element belongs to group 15 (5A). It is a Non metal

c. [Ar]4s23d104p5

Principal quantum number = 4

Number of electrons present = 2 + 5 = 7

This element belongs to group 17 (7A). It is an Halogen.

d. [Kr]5s24d1

This configuration belongs to the element yttrium and has an incomplete d shell. Hence it is a transition metal.

e. [Kr]5s24d105p6

Principal quantum number = 5

Number of electrons present = 2 + 6 = 8

This element belongs to group 18 (8A). It is a Noble gas.