MDCAT Chemistry chapter 10: Chemistry · Chemical bonding MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
51 exam-style questions on Chemistry · Chemical bonding, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Ten Chemistry · Chemical bonding questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. The O–C–O angle in carbon dioxide is 180°, but the O–S–O angle in sulphur dioxide is about 119°. Why?
A
sulphur has a lone pair, so its three regions spread at about 120°
B
sulphur is larger than carbon, so its bonds bend further apart
C
sulphur is sp3 hybridised, so the angle is near 109.5°
D
the S=O bonds are polar, whereas the C=O bonds are non-polar
Show answer
Answer: A. Carbon in CO2 has two regions of electron density and no lone pair, so they lie opposite each other. Sulphur in SO2 has two bonding regions and one lone pair, three regions that repel to about 120°, so the molecule is bent. The C=O bonds are polar too; they cancel because CO2 is linear.
2. According to VSEPR theory, PCl5, with five bond pairs and no lone pair on phosphorus, has the shape
A
square pyramidal
B
octahedral
C
trigonal bipyramidal
D
pentagonal planar
Show answer
Answer: C. Five electron pairs keep as far apart as possible in a trigonal bipyramid: three Cl atoms in a plane at 120° and two axial Cl atoms at 90° to that plane. Six pairs, as in SF6, give an octahedron.
3. Which species is isostructural with BF3, that is, has the same shape?
A
NH3
B
NO3−
C
PCl3
D
H3O+
Show answer
Answer: B. In NO3− the nitrogen atom has three bonding regions and no lone pair, so like BF3 it is trigonal planar with 120° angles. NH3, PCl3 and H3O+ each have a lone pair on the central atom and are pyramidal.
4. Element X has atomic number 12 and element Y has atomic number 9. The compound formed when they react is
A
XY2, with ionic bonding
B
X2Y, with ionic bonding
C
XY, with ionic bonding
D
XY2, with covalent bonding
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Answer: A. X (2,8,2) is a metal that loses two electrons to form X2+; Y (2,7) is a non-metal that gains one electron to form Y−. Two Y− ions balance one X2+ ion, giving the ionic compound XY2 (magnesium fluoride).
5. In the octahedral SF6 molecule, the F–S–F bond angles are
A
90° and 180°
B
120° and 90°
C
109.5° only
D
120° and 180°
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Answer: A. Six bond pairs point to the corners of an octahedron: each F is at 90° to its four neighbours and at 180° to the F opposite it. 120° angles belong to trigonal planar and trigonal bipyramidal shapes.
6. Which of these is an intermolecular force rather than a primary (chemical) bond?
A
the coordinate bond between N and H+ in NH4+
B
the metallic bonding that holds solid zinc together
C
the hydrogen bond between two water molecules
D
the ionic bonding between Na+ and Cl− in salt
Show answer
Answer: C. Ionic, covalent, coordinate and metallic bonds are primary bonds that hold atoms or ions together within a substance. A hydrogen bond is a much weaker attraction between a δ+ hydrogen atom of one molecule and a lone pair on N, O or F of a neighbouring molecule.
7. In the simple model of metallic bonding, what holds a piece of zinc (electronic configuration [Ar]3d104s2) together?
A
Zn2+ ions attracted to a sea of the 4s electrons, delocalised over the whole metal
B
Zn atoms sharing their 4s electrons in localised pairs with each neighbouring atom
C
Zn2+ ions attracted to a sea of the 3d electrons, delocalised over the whole metal
D
separate Zn atoms held together only by weak London dispersion forces
Show answer
Answer: A. Each zinc atom releases its two 4s valence electrons into a sea of electrons that moves through the whole lattice of Zn2+ ions; the attraction between the ions and this mobile sea is the metallic bond. Because the electrons are not held in localised pairs, zinc conducts electricity.
8. Going from HF to HCl to HBr to HI, how do the H–X bond length and the H–X bond energy change?
A
bond length decreases and bond energy increases
B
bond length increases and bond energy decreases
C
bond length and bond energy both increase
D
bond length and bond energy both decrease
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Answer: B. The halogen atom gets larger down the group, so its bonding orbital overlaps less effectively with the hydrogen 1s orbital and the bonding pair is farther from the nucleus: the bond becomes longer and weaker. HF has the shortest, strongest bond and HI the longest, weakest.
9. Using the electronegativities H 2.1, C 2.5, N 3.0, O 3.5 and Cl 3.0, which bond is the most polar?
A
N–H
B
O–H
C
C–Cl
D
C–H
Show answer
Answer: B. Polarity grows with the electronegativity difference: O–H 1.4, N–H 0.9, C–Cl 0.5, C–H 0.4.
10. On the Pauling scale the electronegativities of elements X, Y and Z are 0.9, 3.0 and 2.2. Using the usual electronegativity-difference ranges, the X–Y and Y–Z bonds are best described as
A
polar covalent and ionic
B
ionic and non-polar covalent
C
ionic and polar covalent
D
polar covalent and polar covalent
Show answer
Answer: C. X–Y: 3.0 − 0.9 = 2.1, which is above about 1.7, so the bond is mainly ionic. Y–Z: 3.0 − 2.2 = 0.8, between zero and 1.7, so it is polar covalent; only a zero (or very small) difference gives a non-polar covalent bond.
Chemistry · Chemical bonding: questions students ask
How many Chemistry · Chemical bonding MCQs are there?
51, each with the answer and a short explanation, across 2 topics: Ionic and covalent bonding, Shapes of molecules. Every chapter test draws ten of them, so you can take it many times.
Is the MDCAT Chemistry chapter 10 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
