CHM2046 Final Exam Cheat Sheet – Vocabulary Flashcards

Vocabulary flashcards summarizing periodic trends, group properties, key elements, oxides, industrial processes, and essential reactions for CHM2046 final exam review.

Periodic Trends

General patterns in the periodic table such as increasing ionization energy, more negative electron affinity, and increasing electronegativity across a period.

Ionization Energy

The energy required to remove an electron from an atom; increases across a period and up a group.

Electron Affinity

The energy change when an atom gains an electron; becomes more negative across a period.

Electronegativity

An atom’s ability to attract shared electrons; increases across a period and up a group.

Atomic Radius

Average distance from the nucleus to the outermost electrons; decreases across a period and increases down a group.

Metallic Character

Tendency to lose electrons and form cations; increases down a group.

Hydration Energy

Energy released when ions are solvated by water; higher for small, highly charged ions.

Covalent Oxide

Non-metal oxide that forms an acidic solution when dissolved in water.

Ionic Oxide

Metal oxide that forms a basic solution when dissolved in water.

Amphoteric Oxide

Oxide that reacts with both acids and bases, e.g., Al2O3 and BeO.

Group 1A (Alkali Metals)

Very reactive metals that form hydroxides and hydrogen gas when reacting with water.

Strong Reducing Agent

Species that readily donates electrons; strength increases from Li < Na < K < Cs in Group 1A.

Lithium Reactivity in Air

Forms lithium oxide (Li2O) and lithium nitride (Li3N).

Potassium Superoxide (KO2)

Compound formed when excess O2 reacts with potassium.

Group 2A (Alkaline Earth Metals)

Form strong bases; Ca is more reactive than Mg with water.

Magnesium + Steam

Mg reacts with steam to form MgO and H2.

Calcium + Cold Water

Ca reacts readily with cold water, forming Ca(OH)2 and H2.

Beryllium Oxide (BeO)

Covalent, amphoteric oxide with low electrical conductivity.

Lattice Energy

Energy holding ions in an ionic solid; higher lattice energy lowers solubility of Group 2A salts.

Hydrogen

Most abundant element; flammable gas behaving like Group 1A or 7A.

Ionic Hydride (e.g., NaH)

Compound containing H⁻; reacts with water to give a base and hydrogen gas.

NaH + H2O Reaction

Produces NaOH and H2, raising solution pH.

Group 3A (Boron Family)

Boron is electron-deficient and forms 6-electron species such as B2H6.

Electron-Deficient Compound

Molecule with fewer than eight electrons around the central atom; seen in boranes.

Bridge Bond

B-H-B three-center two-electron bonding found in diborane (B2H6).

Lewis Acid (BF3)

Electron-pair acceptor; BF3 reacts with NH3 as a classic example.

Aluminum Oxide (Al2O3)

Amphoteric oxide that dissolves in both acids and bases.

Diagonal Relationship

Similarity between Be and Al in charge density, amphoterism, and bridge bonding.

Group 4A (Carbon Family)

Elements exhibit oxidation states from +4 to –4 and varied bonding modes.

Graphite

Allotrope of carbon that conducts electricity due to delocalized electrons.

Diamond

Allotrope of carbon that is an electrical insulator with a 3-D network of sp3 bonds.

Graphene

Single layer of sp2-hybridized carbon atoms with high conductivity.

Carbon vs Silicon Bonding

Carbon favors double bonds (C=C); silicon prefers single bonds as in SiO2.

Group 5A (Nitrogen Family)

N is a triple-bonded gas; P is a solid; multiple nitrogen oxides exist.

Nitrogen Oxides Series

Oxides include N2O (+1), NO (+2), N2O3 (+3), NO2/N2O4 (+4), N2O5 (+5).

Ostwald Process Final Step

3 NO2 + H2O → 2 HNO3 + NO for nitric acid production.

Group 6A (Oxygen Family)

Oxidation states range from –2 to +6; O is a gas, S is a solid.

Contact Process

SO3 + H2O → H2SO4, industrial synthesis of sulfuric acid.

Group 7A (Halogens)

Non-metals with decreasing reactivity down the group: F2 > Cl2 > Br2 > I2.

Fluorine

Strongest oxidizer among halogens; forms weakest X–X bond.

Group 8A (Noble Gases)

Inert gases with high ionization energies; only Kr and Xe form compounds.

Cs (Cesium)

Strongest reducing agent in the periodic table.

CaCO3 Decomposition

CaCO3 → CaO + CO2, an important industrial reaction.

PCl3 Hydrolysis

PCl3 + H2O → H3PO3 + HCl, forming phosphorous acid.