WAEC Chemistry Past Questions & Answers - Page 237

1,181.

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

A.

0

B.

1

C.

2

D.

6

E.

8

Correct answer is A

No explanation has been provided for this answer.

1,182.

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

Correct answer is C

No explanation has been provided for this answer.

1,183.

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

Correct answer is A

Tyndall effect, also called Tyndall phenomenon, scattering of a beam of light by a medium containing small suspended particles—e.g., smoke or dust in a room 

1,184.

The following salts will produce a gas on reacting with hydrochloric acid except

A.

CuSO4

B.

CaCO3

C.

FeS

D.

Na2SO3

E.

K2CO3

Correct answer is A

No explanation has been provided for this answer.

1,185.

The following are properties of transition metals except

A.

variable oxidation states

B.

tendency to form complext ions

C.

formation of coloured ions

D.

ability to act as catalyst

E.

low melting points

Correct answer is E

No explanation has been provided for this answer.