Why does an atom of a Group I metal form a 1+ ion?

It loses its single outer electron, leaving the full shell beneath as its outer shell and an excess of one proton over its electrons.

Why is an ionic bond described as non-directional?

The electrostatic attraction of an ion acts equally in every direction, so each ion attracts oppositely charged ions all around it rather than in one fixed direction.

State two factors that make an ionic bond stronger.

An ionic bond is stronger when the ionic charges are larger and when the ionic radii are smaller.

CCEA AS-Level Chemistry 1110

Formulae, Equations and Amounts of Substance

Topic overview Ionic charges and the formulae of compound ions Writing and balancing full and ionic equations The mole, molar mass and Avogadro's constant Reacting masses and reactants in excess Hydrated salts and water of crystallisation

Atomic Structure

Topic overview Protons, neutrons and electrons Atomic number, mass number and the composition of ions Isotopes and relative isotopic mass Relative atomic, molecular and formula mass Mass spectra and relative atomic mass calculations Mass spectra of diatomic elements Electronic configuration and the building up principle Orbitals, electron spin and orbital shapes The s-, p-, d- and f-blocks of the Periodic Table Ionisation energies and their equations Trends in ionisation energy as evidence for shells and subshells

Bonding

Topic overview Ionic bonding and electron transfer Dot and cross diagrams for ionic compounds Covalent bonding and the shared pair Lone pairs and co-ordinate bonding Dot and cross diagrams for covalent molecules and ions The octet rule and its limitations Electronegativity and bond polarity Metallic bonding

Intermolecular Forces and Structure

Topic overview Van der Waals' forces and permanent dipole-dipole attractions Hydrogen bonding, boiling points and solubility Giant ionic, metallic and giant covalent structures Molecular covalent structures and melting points across Period 3

Shapes of Molecules and Ions

Topic overview Electron pair repulsion and VSEPR theory Shapes and bond angles up to four electron pairs Shapes with five and six electron pairs Polar bonds and polar molecules

Redox

Topic overview Rules for assigning oxidation states Oxidation states in peroxides, hydrides and Roman numeral names Oxidation, reduction and electron transfer Oxidising agents, reducing agents and disproportionation Half-equations and combining them into redox equations

The Halogens

Topic overview Colours, physical states and solubility of the halogens Chlorine with water and the treatment of drinking water Disproportionation of the halogens with sodium hydroxide Oxidising ability and displacement reactions Solid halides with concentrated sulfuric and phosphoric acid

Acid-Base Titrations

Topic overview Strong and weak acids and bases Concentration, molarity and units Preparing a standard solution Titration technique, mean titres and uncertainty Indicators and the end point Titration calculations

Qualitative Tests

Topic overview Chemical tests for the gases Flame tests for metal cations Testing for the ammonium ion, sulfate and carbonate Distinguishing the halides, and the starch test for iodine

Formulae and Amounts of a Substance

Topic overview Empirical and molecular formulae Calculating formulae from composition data Molar gas volume and reacting gas volumes Percentage yield Atom economy

Nomenclature and Isomerism in Organic Chemistry

Topic overview Homologous series and functional groups IUPAC rules for naming organic compounds Structural, displayed and skeletal formulae Structural isomerism Geometrical isomerism and E–Z notation

Alkanes

Topic overview Alkanes as saturated hydrocarbons Boiling points of alkanes and van der Waals' forces Boiling points of branched isomers Complete and incomplete combustion of alkanes Pollutants from alkane fuels and the atmosphere Catalytic converters Radicals, homolytic fission and heterolytic fission Free radical substitution of alkanes

Alkenes

Topic overview Unsaturated hydrocarbons and the bromine water test Sigma and pi bonds in the carbon–carbon double bond Electron density at C=C, reactivity and catalytic hydrogenation Addition of chlorine and bromine to alkenes Addition of hydrogen chloride and hydrogen bromide Electrophiles, heterolytic fission and the addition mechanism Carbocation stability and Markovnikov addition Addition polymerisation of alkenes

Halogenoalkanes

Topic overview Classification and boiling points of halogenoalkanes Laboratory preparation of a halogenoalkane from an alcohol Nucleophiles and hydrolysis with aqueous alkali Reactions with ammonia and with potassium cyanide Relative rates of hydrolysis and carbon–halogen bond enthalpy Elimination using ethanolic potassium hydroxide CFCs and the ozone layer

Alcohols

Topic overview Hydrogen bonding, boiling point and solubility of alcohols Classifying alcohols and preparing them from halogenoalkanes Combustion of alcohols and their use as fuels Reactions with sodium, hydrogen bromide and phosphorus pentachloride Oxidation with acidified potassium dichromate(VI)

Infrared Spectroscopy

Topic overview Molecular vibrations and the absorption of infrared radiation Characteristic absorptions and the wavenumber scale Identifying functional groups from infrared spectra Distinguishing compounds and following reactions by infrared

Energetics

Topic overview Exothermic and endothermic changes Standard conditions and the standard enthalpy change Enthalpy level diagrams Standard enthalpies of combustion and formation Standard enthalpy of neutralisation Measuring enthalpy changes by experiment Enthalpy calculations using q = mcΔT Hess's Law and enthalpy cycles Indirect enthalpy calculations using Hess's Law Average bond enthalpies and their limitations

Kinetics

Topic overview Reaction rate and the factors that change it Collision theory and activation energy The Maxwell–Boltzmann distribution of molecular energies Catalysts and the activation energy barrier

Equilibrium

Topic overview Reversible reactions and dynamic equilibrium Changing conditions and the position of equilibrium The equilibrium constant Kc and its units The magnitude of Kc and the extent of reaction Industrial processes and compromise conditions

Group II Elements and Their Compounds

Topic overview s-block character and electronic configuration Trends in atomic radius and first ionisation energy Reactions of the elements with oxygen, water and dilute acids The oxides and their reactions with water and dilute acids Thermal stability of the carbonates and hydroxides Uses of magnesium oxide, calcium carbonate and lime Solubility trends and solubility curves

Bonding

8 subtopics
24 things to know
Unit AS 1

What Bonding covers

Bonding is examined in Unit AS 1, Basic Concepts in Physical and Inorganic Chemistry, and drawn on again in Unit AS 3, Basic Practical Chemistry. It covers ionic bonding and electron transfer, dot and cross diagrams for ionic compounds, covalent bonding and the shared pair, lone pairs and co-ordinate bonding, dot and cross diagrams for covalent molecules and ions, the octet rule and its limitations, electronegativity and bond polarity and metallic bonding.

Where it is assessed

Unit AS 1

Basic Concepts in Physical and Inorganic Chemistry, and again in Unit AS 3, Basic Practical Chemistry.

Check the CCEA specification ↗

The 8 subtopics

Each one has its own page. CCEA AS Chemistry students sit this topic in the first year.

What you need to know

Answer each one before you reveal it.

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Key term

What is a covalent bond, between which kinds of element does it form, and how do double and triple bonds differ?

Key term

Describe the dot and cross diagram of the ammonium ion.

Key term

Define ionic bonding.

Key term

What is the purpose of using dots for one atom's electrons and crosses for the other's?

Key term

Define the term lone pair.

Key term

State the octet rule.

Key term

Define electronegativity.

Key term

Define metallic bonding.

Key term

Which types of element normally combine to form an ionic compound?

Key term

In a dot and cross diagram of sodium chloride, how is the chloride ion shown?

Key term

Explain what a covalent bond is.

Key term

What is required of the atom that accepts a co-ordinate bond?

Key term

What does the overlap region of two circles represent in a covalent dot and cross diagram?

Key term

Which element is a routine exception to the octet rule because its shell is full at two electrons?

Key term

Describe the trend in electronegativity down a group, and explain it.

Key term

What is meant by describing the electrons in a metal as delocalised?

Key term

Explain what happens to the electrons when sodium reacts with chlorine.

Key term

Why are square brackets and a charge always written around an ion in these diagrams?

Key term

Which types of element normally form covalent bonds with each other?

Key term

Why can a molecule with no lone pair, such as methane, not form a co-ordinate bond as the donor?

Key term

Describe the dot and cross diagram of a chlorine molecule.

Key term

How many electrons surround the beryllium atom in BeCl₂?

Key term

Name the most electronegative element.

Key term

Explain why metals conduct electricity in the solid state.

Take Bonding further

The same content, four other ways.

Questions from this topic

Each one with the model answer underneath.

1
Define ionic bonding.
Model answer
Ionic bonding is the electrostatic attraction between oppositely charged ions formed by the transfer of electrons.
2
Which types of element normally combine to form an ionic compound?
Model answer
A metal, which loses electrons, normally combines with a non-metal, which gains them.
3
Why does an atom of a Group I metal form a 1+ ion?
Model answer
It loses its single outer electron, leaving the full shell beneath as its outer shell and an excess of one proton over its electrons.
4
Explain what happens to the electrons when sodium reacts with chlorine.
Model answer
Each sodium atom transfers one electron to a chlorine atom, forming Na⁺ and Cl⁻ ions that are then attracted to one another.
5
Why is an ionic bond described as non-directional?
Model answer
The electrostatic attraction of an ion acts equally in every direction, so each ion attracts oppositely charged ions all around it rather than in one fixed direction.
6
State two factors that make an ionic bond stronger.
Model answer
An ionic bond is stronger when the ionic charges are larger and when the ionic radii are smaller.

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Formulae, Equations and Amounts of Substance

Atomic Structure

Bonding

Intermolecular Forces and Structure

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AThe reactants total 159.6 + 84.0 = 243.6.

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Bonding revision questions

Is Bonding examined at AS in CCEA Chemistry?: Yes. It sits in Unit AS 1, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.
What does Bonding cover in CCEA AS-Level Chemistry?: 8 subtopics: ionic bonding and electron transfer, dot and cross diagrams for ionic compounds, covalent bonding and the shared pair, lone pairs and co-ordinate bonding, dot and cross diagrams for covalent molecules and ions, the octet rule and its limitations, electronegativity and bond polarity and metallic bonding. Each one has its own page with questions and model answers.
How is Bonding organised?: By the CCEA 1110 specification, subtopic by subtopic, so it matches the order you are taught it in.

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