Chemistry 2020 Waec Past Questions and Answers

Question 41 :

• WAEC 2020

Which of the following arrangement of elements is in decreasing order of electronegativity?

A. Na, Mg, Al, Si, P
B. Na, A1, Mg, P, Si
C. P, Mg, Na, Si, Al
D. P, Si, Al, Mg, Na

Question 42 :

• WAEC 2020

The metallic bond in magnesium is stronger than that in calcium because magnesium has a

A. Larger atomic size.
B. Smaller atomic size
C. Greater number of valence electrons
D. Lower melting point

Question 43 :

• WAEC 2020

Consider the reaction represented by the following equation:
AgNO\(_3\) + NaCl → AgCl + NaNO\(_3\).
The steps that could be taken to obtain pure dry sample of AgCI (s) from the mixture includes

A. Heating to saturation and drying
B. Filtering and evaporation to dryness
C. Filtering, washing and drying
D. Crystallizing and allowing to cool

Question 44 :

• WAEC 2020

How many electrons does \({31}_{15}\)P\(^3-\) contain?

A. 12
B. 15
C. 16
D. 18

Question 45 :

• WAEC 2020

The atomic number of an atom would be equal to its mass number if it

A. Has a totally filled valence shell
B. Has a high charge to mass ratio
C. Does not contain neutrons
D. Exhibits isotopy