What is a covalent bond?
2 marks · NormalState what is meant by a covalent bond. Explain the mechanism by which a covalent bond forms between two atoms.
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A covalent bond is formed when two atoms share a pair of electrons. The covalent bond forms due to the strong electrostatic attraction between the positively charged nuclei of the atoms and the negatively charged shared electrons.
Also accept: A covalent bond involves sharing a pair of electrons between atoms.; The shared pair of electrons is attracted to the nuclei of both bonded atoms.
Common mistakes: Describing electron transfer instead of sharing.; Omitting the role of electrostatic attraction.
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Marking points
B1 · 1 mark · Correctly defines a covalent bond as a shared pair of electrons.
B2 · 1 mark · Explains attraction between nuclei and shared electron pair (electrostatic attraction mechanism).
Worked solution
A covalent bond is formed when two atoms share a pair of electrons (B1).
The bond is held together by the strong electrostatic attraction between the positively charged nuclei of the atoms and the negatively charged shared electrons (B2).