Topic 4: Bonding Flashcards

Comprehensive vocabulary flashcards covering Topic 4: Bonding, including ionic, covalent, and metallic structures, VSEPR shapes, and intermolecular forces.

Cations

Positive ions that form by metals losing valence electrons.

Anions

Negative ions that form by non-metals gaining electrons.

Ionic bond

The electrostatic attraction between oppositely charged ions.

Ionic lattice

A repeating (continuous) array into which ions are packed in a solid ionic compound.

Polyatomic ions

Ions consisting of multiple atoms, such as $NH_4^+$ (ammonium), $OH^-$ (hydroxide), $NO_3^-$ (nitrate), $HCO_3^-$ (hydrogen carbonate), $CO_3^{2-}$ (carbonate), $SO_4^{2-}$ (sulphate), and $PO_4^{3-}$ (phosphate).

The 1.7 Rule

A guideline used to determine if a bond is ionic based on the electronegativity difference between atoms.

Multivalent ions

Ions that can have more than one charge, such as $Fe^{2+}$ and $Fe^{3+}$.

Covalent bond

The electrostatic attraction between a shared pair of electrons and the positively charged nuclei.

Octet rule

The tendency of atoms to gain a valence shell with a total of $8$ electrons.

Resonance structures

Occur when there is more than one possible position for a double bond in a molecule.

VSEPR theory

Valence Shell Electron Pair Repulsion theory, used to determine shapes of molecules based on the repulsion of electron pairs.

Electron domain

The term used in place of 'negative charge centre' to describe regions of electron density around an atom.

Non-polar covalent bond

A bond formed by the equal sharing of electrons between atoms.

Polar covalent bond

A bond formed by the unequal sharing of electrons due to a difference in electronegativities.

Coordinate covalent bond (dative)

A covalent bond in which both electrons shared in the bond come from the same atom.

Free Radicals

A molecule or particle with an odd amount of electrons or a broken bond, making it very unstable and reactive.

Linear

A molecular shape with $2$ bonding electron pairs and a bond angle of $180^\text{o}$.

Trigonal Planar

A molecular shape with $3$ bonding pairs and $0$ lone pairs, resulting in a bond angle of $120^\text{o}$.

Bent

A molecular shape with $2$ bonding pairs and $2$ lone pairs, resulting in a bond angle of approximately $104.5^\text{o}$.

Pyramidal

A molecular shape with $3$ bonding pairs and $1$ lone pair, resulting in a bond angle of approximately $107.3^\text{o}$.

Tetrahedral

A molecular shape with $4$ bonding pairs and a bond angle of $109.5^\text{o}$.

Bond enthalpy

The energy required to break a bond as a gas, measured in $kJ/mol$.

Bond length

The distance between nuclei at the balance of attractive and repulsive forces, measured in $pm$ or $\text{\text{Å}}$.

Allotropes

Different forms of the same element where atoms are bonded together in a different manner, such as diamond, graphite, and fullerenes for carbon.

Diamond

An allotrope of carbon with a tetrahedral lattice arrangement (3D framework) that does not conduct electricity.

Graphite

An allotrope of carbon with a sheet-like structure (2D framework) that is soft and conducts electricity.

Graphene

A one-atom thick layer of graphite that is remarkably strong and highly efficient at conducting heat and electricity.

Fullerene $C_{60}$

Also known as buckminsterfullerene, it consists of $60$ carbon atoms bonded in a nearly spherical configuration.

Intramolecular forces

Forces (bonds) that exist within each molecule and influence the chemical properties of a substance.

Intermolecular forces

Forces that exist between molecules and influence the physical properties of a substance, such as boiling point.

London (dispersion) forces

The weakest intermolecular forces resulting from instantaneous induced dipoles between non-polar entities.

Dipole-dipole forces

The electrostatic attraction between the oppositely charged ends of polar molecules.

Hydrogen bonding

The strongest intermolecular force, occurring between hydrogen attached to an electronegative atom (N, O, or F) and a lone pair on an electronegative atom of another molecule.

Metallic bond

The electrostatic attraction between a lattice of positive ions and delocalized electrons.

Delocalised electrons

Electrons in a metal that do not belong to one atom and are free to move throughout the piece of metal.

Alloys

Materials containing more than one metal (or a metal and non-metal) with enhanced properties, like steel being stronger than pure iron.

Volatility

A measure of how readily a liquid or solid is vaporized upon heating or evaporation.

Malleability

The ability of metal layers to slide past each other without breaking bonds, allowing it to be hammered into sheets.