Fundamentals of Chemistry Quick Revision

Flashcards covering key vocabulary and definitions from the chemistry quick revision notes.

Ions

Atoms with Unequal protons/electrons; can be positively charged (Cations) or negatively charged (Anions)

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Compound

Atoms bonded together through covalent (shared electrons) or ionic (transferred electrons) bonds.

Ionic bonds

Bond formed between a metal and a nonmetal, characterized by a strong lattice structure and a high melting point.

Covalent bonds

Bond formed between nonmetals, involving shared electrons, directional properties, and a low melting point.

Metallic bonding

Bonding with delocalized electrons, leading to conductivity and malleability.

Van der Waals forces

Weak forces between molecules categorized into Keesom (dipole-dipole), Debye (dipole-induced dipole), and London (temporary dipoles) forces.

Hydrogen bonding

Strong dipole-dipole interaction specifically involving H bonded to N, O, or F.

Polar molecules

Having an asymmetrical shape or bond dipoles that do not cancel out, leading to an uneven charge distribution.

Nonpolar molecules

Having a symmetrical shape where dipoles cancel out, resulting in no net dipole moment.

Valence electrons

Outer shell electrons involved in bonding.

Skeletal formula

Shows non-hydrogen and non-carbon atoms, where carbon atoms form four bonds.

Double bonds

A stronger and shorter bond with no rotation.

Isomers

Molecules with the same formula but different structures (e.g., cis/trans).

Mole

6.022 × 10²³ particles (Avogadro's constant).

% Yield

(actual yield ÷ theoretical yield) × 100.

Stoichiometry

Ratio of reactants/products determined by balanced equations.

Meth-

Prefix used to indicate a carbon chain of 1 carbon.

Eth-

Prefix used to indicate a carbon chain of 2 carbons.

Prop-

Prefix used to indicate a carbon chain of 3 carbons.

But-

Prefix used to indicate a carbon chain of 4 carbons.

-ane

Suffix for alkanes (C-C single bonds)

-ene

Suffix for alkenes (C=C double bonds)

-ol

Suffix for alcohols

photons

Discrete packets of energy that light is composed of.

Wave-Particle Duality

Light exhibits both wave and particle characteristics.

Bohr Model

The principle that electrons exist in specific, quantized energy levels within an atom.

Quantum Mechanics

Describes how energy is quantized, and wave functions describe energy levels.

Core electrons

Electrons that are tightly bound and non-bonding.

Valence electrons

Electrons in the outer shell that are involved in bonding.

Z_eff

The effective nuclear charge, which is reduced by inner electrons.

Particle in a Box Model

Explains that a larger box results in lower energy levels.

Orbital Overlap & Bonding

States bonds form when potential wells/orbitals overlap; strong when energies and depths are similar, weak/none if dissimilar.

LCAO (Linear Combination of Atomic Orbitals)

A method where atomic orbitals combine to form bonding and anti-bonding orbitals.

Bonding

Atomic orbitals combine → bonding & anti-bonding orbitals; lower energy

Anti-bonding

Atomic orbitals combine → bonding & anti-bonding orbitals; higher energy

MO Diagrams

Shows orbital energy levels

Bonding orbital

Constructive interference → more delocalisation → lower energy

Anti-bonding orbital

Destructive interference → less delocalisation → higher energy

Bond order

(bonding e – antibonding e)/2

Valence Orbitals

Determine bonding and reactivity

LCAO Rules

n atomic orbitals → n molecular orbitals

HOMO

highest occupied MO

LUMO

lowest unoccupied MO

SOMO

singly occupied MO

Hybrid Atomic Orbitals (HAOs)

Formed by mixing s and p orbitals ; Used to model geometry (e.g., sp³ = tetrahedral)

Ethane

sp³ → single σ bonds → free rotation

Ethene

sp² + π → flat → no rotation (π bond breaks)

σ orbitals

symmetric around bond axis

π orbitals

above/below bond axis

g (gerade)

symmetric through inversion

u (ungerade)

asymmetric through inversion

Magnetism

Unpaired e → magnetic

s–p Mixing

Happens when 2s and 2p energies are close (light atoms)

XPS

probes core electrons (X-rays)

UPS

probes valence electrons (UV)

Molecular Orbital Diagrams

Energy overlap and number of atomic orbitals determines number and strength of MOs.

Peptide bonds

planar, partial double-bond character, sp² hybridisation

Electronegativity & Bonding Trends

x increases → orbitals lower in energy; large Δx → ionic bonding; Small Δx → covalent bonding

Metals

Metals are large, high-energy orbitals → weak electron holding (electropositive)

Octet rule

atoms tend to complete outer shell (8e)

Lewis acid

electron pair acceptor

Lewis base

donor

Conjugation

adjacent p-orbitals or lone pairs; increases stability

Hückel rule

(4n + 2) π-electrons → aromatic

Selection rules

no spin change allowed; parity must change (g↔u) o Dipole change must occur for transitions

Metals

partially filled bands → conduct

Insulators

full bands → don’t conduct

Semiconductors

small band gap; doping → n-type = extra electrons; p-type = extra holes

Phase Diagrams

Solids = high pressure; Gases/liquids = high temp