Jamb Chemistry 1991 Past Questions and Answers

Question 11:

• JAMB 1991

The electronic configuration of an elements is 1s²2s²2p⁶3s²3p³. How many unpaired electrons are there in the element?

A. 5
B. 4
C. 3
D. 2

Question 12:

• JAMB 1991

The ions X_- and Y₊ are isoelectronic, each containing a total of 10 electrons.
How many protons are in the nuclei of the neutral atoms of X and Y respectively?

A. 10 and 10
B. 9 and 9
C. 11 and 9
D. 9 and 11

Question 13:

• JAMB 1991

Which of the following represents the type of bonding present in ammonium chloride molecule?

A. Ionic only
B. Covalent only
C. Ionic and dative covalent
D. Dative covalent only

Question 14:

• JAMB 1991

Which of the following is arranged in order of increasing electronegativity?

A. Chlorine, aluminium, magnesium, phosphorus, sodium
B. Sodium, magnesium, aluminium, phosphorus, chlorine
C. Chlorine, phosphorus, phosphorous, aluminium, magnesium, sodium
D. Sodium, chlorine, phosphorus, magnesium, aluminium

Question 15:

• JAMB 1991

A quantity of air was passed through a weighed amount of alkaline pyrogallol. An increase in the weight of the pyrogallol would result from the absorption of?

A. Nitrogen
B. Neon
C. Argon
D. Oxygen