Question

1. What is the name given to group 17 elements? Why are they called so?

2. Comment on the-

(a) Reactivity

(b) Colour

(c) Physical state of group 17 elements.

Answer 1

Part 1: Name of Group 17 element

• The name of group 17 is Halogen and halogen means ‘salt producing’
• Halogens combine with metals to produce salts that why they are provided with the name halogen.
• For example: Chloride combines with sodium to form sodium chloride(NaCl)

Part: 2

(a) Reactivity of halogen:

• The elements in group 17 are very reactive in nature because they have 7 electrons in their outer shell and they need only one electron to complete their octet.
• As we move down in a group the reactivity of halogens decreases because the size of the element increases and the capacity to gain electrons decreases hence reactivity decreases.

(b) The colour of halogens are as follows:

• Flourine: Pale yellow
• Chlorine: Greenish yellow
• Bromine: Reddish brown
• Iodine: Violet

(c) The physical state of halogens is as follows:

• Flourine: Gas
• Chlorine: Gas
• Bromine: Liquid
• Iodine: Solid
• Astatine: Very rare element