Ch 4Chemical Bonding and Molecular Structure — Class 11 Chemistry, concept-first.

The electrons that occupy the outermost shell of an atom are called valence electrons, and it is these electrons — not the inner, tightly-held core electrons — that participate in chemical bonding.

An ionic (or electrovalent) bond forms when one atom transfers one or more valence electrons completely to another atom, generating a positively charged ion (a cation) and a negatively charged ion (an…

Once atoms are joined by a covalent bond, that bond can be described quantitatively using four standard bond parameters.

A covalent bond forms when two atoms — typically two non-metals of comparable electronegativity — share one or more pairs of electrons, rather than one atom transferring electrons to the other outrigh…

No real bond between two different atoms is ever purely covalent (perfectly equal sharing) or purely ionic (complete electron transfer) — both are idealised limits, and most actual bonds lie somewhere…

Valence bond theory (VBT), developed principally by Heitler and London and extended by Pauling and Slater, offers a physical, orbital-based picture of how a covalent bond actually forms, going beyond…

For some molecules and polyatomic ions, no single Lewis structure — however carefully drawn — can correctly represent the true distribution of electrons and bonds.

The Valence Shell Electron Pair Repulsion (VSEPR) theory is a simple but remarkably powerful model for predicting the three-dimensional shape of a covalent molecule directly from its Lewis structure,…

VSEPR theory correctly predicts molecular shape, but it says nothing about why a central atom's orbitals — ordinarily an orbital and three separate, differently-shaped orbitals — should produce bonds…

The , and hybridisation schemes account for every case where a central atom is surrounded by two, three or four electron pairs — but some central atoms, especially those from period 3 and beyond that…

Ionic and covalent bonds hold the atoms within a molecule together, and they are strong — typically hundreds of kilojoules per mole.

Hydrogen bonding is a particularly strong type of dipole–dipole intermolecular attraction that arises under a very specific condition: hydrogen must be covalently bonded directly to one of the three s…

Valence bond theory, as this chapter's earlier section noted, cannot explain the paramagnetism of , because it always predicts fully paired electrons.

Sample papers and previous-year board questions for this subject.