Question

Identify the non-metal which is liquid at room temperature.
A. Br
B. F
C. Cl
D. None of these

Answer 1

Hint: As you can see, all options given to us are halogens (group 17 elements). Therefore, justify the physical state of the elements on the basis of forces acting between them.

Complete step by step answer:
Fluorine and Chlorine are gases, Bromine is a liquid and Iodine is a solid. It is because-
Bromine exists as a diatomic molecule. It has a greater atomic radius than chlorine and fluorine.
Because of a greater atomic radius, it has a greater surface area around the bromine atoms
Therefore, greater Vander Waals forces act between the diatomic bromine molecules.
As a result of this, more energy is needed to overcome the greater Vander Waals forces.
Hence, bromine has a higher boiling point and is a liquid at room temperature.
Therefore, the answer is – option (A) – Bromine is a non-metal that is liquid at room temperature.

Additional Information:
All noble gases (group 18 elements) are gases.

Note: Bromine is a p-block element, belonging to period 4 and group 17 of the periodic table. It is a reddish-brown liquid, with a melting point of -7.2 degree Celsius and boiling point of 58.8 degree Celsius. Other than bromine, mercury is an element which is liquid at room temperature.