Covalent Bonding and Structures

Twelve Q&A flashcards covering definitions, formation, types, representations, properties, and factors related to covalent bonds and structures.

What is covalent bonding?

It is the strong electrostatic attraction between two nuclei and a shared pair of electrons, usually occurring between non-metal atoms.

How is a covalent bond formed?

Two atoms share one or more pairs of electrons so each attains a full outer (noble-gas) shell.

What distinguishes single, double, and triple covalent bonds?

Single bond – one shared pair of electrons; Double bond – two shared pairs; Triple bond – three shared pairs.

What is a dative (coordinate) covalent bond?

A covalent bond in which both electrons in the shared pair originate from the same atom, e.g., N→H bond in NH₄⁺.

How are normal and dative covalent bonds shown in diagrams?

Normal bonds by a line (–); dative bonds by an arrow pointing from the donor atom toward the acceptor atom.

What are the key properties of simple molecular (covalent) substances?

Low melting/boiling points (weak intermolecular forces), non-conductors of electricity, usually soluble in non-polar solvents and insoluble in water.

What is a giant covalent structure?

A 3-D lattice where atoms are joined by covalent bonds in a continuous network, e.g., diamond, graphite, SiO₂.

What are the properties of giant covalent structures?

Very high melting/boiling points, generally hard and water-insoluble, do not conduct electricity except graphite.

Why does graphite conduct electricity whereas diamond does not?

Graphite has one delocalised electron per carbon that can move and carry charge; diamond has all four valence electrons tied up in bonds, leaving no free electrons.

How do bond length and strength vary from single to triple bonds?

Single bonds are longest and weakest; double bonds are shorter and stronger; triple bonds are shortest and strongest.

Which factors influence covalent bond strength?

Number of shared electrons (more = stronger), atomic radius (smaller atoms = stronger), and bond polarity (greater polarity can increase attraction).

What is bond polarity?

Unequal sharing of electrons due to a difference in electronegativity between the bonded atoms, creating a polar bond.