What is a covalent bond?
2 marks · HardExplain what a covalent bond is and describe how the sharing of electrons holds the bonded atoms together.
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A covalent bond is a chemical bond formed when two atoms share a pair of electrons. The atoms are held together by the strong electrostatic attraction between the positively charged nuclei and the negatively charged shared pair of electrons.
Also accept: A covalent bond is formed by sharing a pair of electrons between two atoms, and this pair is attracted to both nuclei, holding the atoms together.; In a covalent bond, atoms share electrons; the bond is caused by attraction between the shared electrons and the nuclei of both atoms.
Common mistakes: Only mentioning sharing of electrons but not the electrostatic attraction.; Describing only one atom's involvement or that only one atom supplies both electrons (in general definition).
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Marking points
B1 · 1 mark · Defines a covalent bond as a bond formed by sharing a pair of electrons between atoms.
B2 · 1 mark · Explains the mechanism: strong electrostatic attraction between the nuclei and the shared pair of electrons holds the atoms together.
Worked solution
A covalent bond is a chemical bond formed when two atoms share a pair of electrons.
The shared electrons are attracted to both nuclei, and this electrostatic attraction between the nuclei and the shared pair of electrons holds the atoms together.