The phenomenon observed when dust particles collide randomly in a beam of sunlight is known as

A. Tyndal effect

B. diffusion

C. osmosis

D. brownian movement

E. dialysis

The mass number of an element is the sum of its

A. electrons, neutrons and protons

B. electrons and protons

C. protons and neutrons

D. orbital electrons

E. valence electrons

How many unpaired electrons are there in an atom of an element with the following electronic configuration? 1s²2s²2p₆

A. o

B. 1

C. 2

D. 6

E. 8

Radon is used as a tracer in medical research because it

A. is monatomic

B. is radioactive

C. is a noble gas

D. has a complete valence shell

E. has a low boiling point

What is the most probable group of an element which is a soft, silvery white solid and reacts violently with water?

A. Group 0

B. Group 1

C. Group 4

D. Group 6

E. Group 7

In linear molecules, the bond angle is

A. 90^o

B. 140^o

C. 109^o

D. 120^o

E. 180^o

A sodium atom and a sodium ion have the same

A. number of neutrons

B. number of electrons

C. electric charge

D. electronic structure

E. chemical properties

If the atomic number of an element X is 11 and that of nitrogen is 7, the most likely formula of the nitride of X is

A. X₃N

B. XN₃

C. X₃N₂

D. N₂X

E. NX₂

An increase in the pressure of a gas results in a decrease in its

A. mass

B. vapour density

C. volume

D. temperature

E. concentration

A given volume of methane diffuses in 20 seconds. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions? [CH4 = 16; SO2 = 64]

A. 5 seconds

B. 20 seconds

C. 40 seconds

D. 60 seconds

E. 80 seconds