Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
The atomic number of an atom would be equal to its mass number if it
has a totally filled valence shell
has a high charge to mass ratio
does not contain neutrons
exhibits isotopy
Correct answer is C
- The mass number of an atom is its total number of protons and neutrons
How many electrons does 3115P3− contain?
12
15
16
18
Correct answer is D
- Phosphorus also has 15 electrons.
- Here we have P3- which means that this atom has gained 3 electrons. So, P3- has 18 electrons.
Consider the reaction represented by the following equation:
AgNO3 + NaCl → AgCl + NaNO3.
The steps that could be taken to obtain pure dry sample of AgCI (s) from the mixture includes
heating to saturation and drying
filtering and evaporation to dryness
filtering, washing and drying
crystallizing and allowing to cool
Correct answer is C
No explanation has been provided for this answer.
The metallic bond in magnesium is stronger than that in calcium because magnesium has a
larger atomic size.
smaller atomic size
greater number of valence electrons
lower melting point
Correct answer is B
- Magnessium has a stronger metallic bond than calcium because it has smaller atomic radius.
- Atomic radius decreases across a period and increases down a group.
Which of the following arrangement of elements is in decreasing order of electronegativity?
Na, Mg, Al, Si, P
Na, A1, Mg, P, Si
P, Mg, Na, Si, Al
P, Si, Al, Mg, Na
Correct answer is D
- Reactivity series is K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au.
-Very Electropositive Metals Most active metals have low electronegativities