Nimo

Study smarter with Nimo

Personalised revision that adapts to you. Ace your revision with unlimited practice questions that are designed to help you learn faster. We're slowly rolling out to more and more students.

Try Nimo

Covalent bonding and small molecules

Bonding, structure and the properties of matter • Chemical bonds

Key concepts

What you'll likely be quizzed about

  • Covalent bonding occurs when two non-metal atoms share pairs of electrons.
  • This sharing creates a more stable electron arrangement for both atoms by filling their outer shells, often achieving a configuration similar to that of noble gases.
  • The strength and length of covalent bonds vary: single bonds involve one shared pair, double bonds consist of two shared pairs, and triple bonds include three pairs, resulting in stronger and shorter bonds.

Flashcards

Test your knowledge with interactive flashcards

How many covalent bonds does nitrogen form in ammonia (NH3)?

Click to reveal answer

Nitrogen forms three single covalent bonds to three hydrogen atoms in NH3.

Key notes

Important points to keep in mind

Covalent bonding = sharing electron pairs to achieve full outer shells.

Single bond = one shared pair (shown as a line); double bond = two pairs; triple bond = three pairs.

Dot-and-cross diagrams show electron origins; only outer-shell electrons are represented.

Count atom symbols in diagrams to deduce the molecular formula.

H forms 1 bond, O forms 2, N forms 3, C forms 4, Cl forms 1 (typical patterns).

Small molecules typically exhibit low melting and boiling points due to weak intermolecular forces.

Hydrogen bonding (in H2O and NH3) raises boiling points compared to similar-sized molecules.

Line-bond diagrams simplify structures for quick formula deduction.

Lone pairs (non-bonding electrons) affect molecular shape.

Discrete molecules have fixed molecular formulae; giant networks do not.

Built with v0