Atomic structure, chemical bonding and the properties of structures

Explain what the atomic number represents (the atomic number is…)

The atomic number is the number of protons in the nucleus and it defines the element

Describe what the mass number shows (the mass number shows…)

The mass number shows the total number of protons and neutrons in an atom

Explain what isotopes are (isotopes are…)

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons

Compare isotopes of an element (isotopes differ because…)

Isotopes differ because they have different neutron numbers but identical chemical behaviour

Describe the structure of an atom (an atom contains…)

An atom contains a nucleus of protons and neutrons surrounded by electrons in energy levels

Explain why atoms are neutral (atoms are neutral because…)

Atoms are neutral because they contain equal numbers of protons and electrons

Describe electron shells (electron shells are…)

Electron shells are fixed energy levels that electrons occupy around the nucleus

Explain how electron configuration affects reactivity (reactivity is influenced because…)

Reactivity is influenced because atoms with incomplete outer shells tend to gain, lose or share electrons

Explain how group number links to electrons (group number tells us…)

Group number tells us the number of electrons in the outer shell

Describe how ions form (ions form when…)

Ions form when atoms gain or lose electrons to achieve a stable electronic structure

Explain why metals form positive ions (metals form positive ions because…)

Metals form positive ions because they lose electrons from their outer shell

Explain why non‑metals form negative ions (non‑metals form negative ions because…)

Non‑metals form negative ions because they gain electrons to fill their outer shell

Describe ionic bonding (ionic bonding is…)

Ionic bonding is the electrostatic attraction between oppositely charged ions

Explain how ionic lattices form (ionic lattices form when…)

Ionic lattices form when many ions arrange in a repeating giant structure held by electrostatic forces

Explain why ionic compounds have high melting points (they have high melting points because…)

They have high melting points because strong electrostatic forces require large amounts of energy to overcome

Compare conductivity of ionic compounds (ionic compounds conduct when…)

Ionic compounds conduct when molten or dissolved because ions are free to move

Describe covalent bonding (covalent bonding is…)

Covalent bonding is the sharing of electron pairs between non‑metal atoms

Explain why simple covalent molecules have low melting points (they melt easily because…)

They melt easily because weak intermolecular forces require little energy to overcome

Compare covalent bonds and intermolecular forces (covalent bonds are…, intermolecular forces are…)

Covalent bonds are strong bonds within molecules, whereas intermolecular forces are weak attractions between molecules

Describe giant covalent structures (giant covalent structures consist of…)

Giant covalent structures consist of many atoms joined by strong covalent bonds in a continuous network

Explain why diamond is hard (diamond is hard because…)

Diamond is hard because each carbon forms four strong covalent bonds in a rigid tetrahedral structure

Explain why diamond does not conduct electricity (diamond cannot conduct because…)

Diamond cannot conduct because it has no delocalised electrons

Describe the structure of graphite (graphite consists of…)

Graphite consists of layers of carbon atoms arranged in hexagons with delocalised electrons

Explain why graphite conducts electricity (graphite conducts because…)

Graphite conducts because delocalised electrons can move through the structure

Explain why graphite is soft (graphite is soft because…)

Graphite is soft because weak forces allow layers to slide over each other

Describe graphene (graphene is…)

Graphene is a single layer of carbon atoms arranged in a hexagonal lattice

Explain why graphene is strong (graphene is strong because…)

Graphene is strong because of its network of strong covalent bonds

Describe fullerenes (fullerenes are…)

Fullerenes are hollow carbon molecules that can trap or carry substances

Explain how fullerenes can deliver drugs (they deliver drugs because…)

They deliver drugs because their hollow structure can contain therapeutic molecules

Define nanoparticles (nanoparticles are…)

Nanoparticles are particles sized between 1–100 nm with a very large surface area to volume ratio

Explain why nanoparticles are more reactive (they are more reactive because…)

They are more reactive because a greater proportion of atoms are exposed at the surface

Describe uses of nanoparticles (nanoparticles are used for…)

Nanoparticles are used for catalysts, drug delivery, electronics and sun creams

Explain risks of nanoparticles (risks exist because…)

Risks exist because nanoparticles may enter cells and cause unknown long‑term effects

Describe metallic bonding (metallic bonding is…)

Metallic bonding is the attraction between positive metal ions and delocalised electrons

Explain why metals conduct electricity (metals conduct because…)

Metals conduct because delocalised electrons can move freely through the structure

Explain why metals are malleable (metals are malleable because…)

Metals are malleable because layers of ions can slide while remaining bonded by delocalised electrons

Compare properties of metals and non‑metals (metals typically…, non‑metals typically…)

Metals typically conduct and are malleable, whereas non‑metals are often brittle and insulating

Describe alloys (alloys are…)

Alloys are mixtures of metals that contain atoms of different sizes

Explain why alloys are harder than pure metals (alloys are harder because…)

Alloys are harder because different‑sized atoms distort layers and prevent them sliding

Describe steel (steel is…)

Steel is an alloy of iron with controlled amounts of carbon and other elements

Explain corrosion (corrosion occurs when…)

Corrosion occurs when metals react with oxygen and water, forming oxides

Explain how rusting occurs (rusting happens because…)

Rusting happens because iron reacts with oxygen and water to form hydrated iron(III) oxide

Describe methods to prevent corrosion (corrosion can be prevented by…)

Corrosion can be prevented by barriers, sacrificial protection or galvanising

Explain sacrificial protection (sacrificial protection works because…)

Sacrificial protection works because a more reactive metal corrodes instead of iron

Describe the plum pudding model (the plum pudding model suggested…)

The plum pudding model suggested atoms were spheres of positive charge with electrons embedded

Explain how the nuclear model was developed (the nuclear model was developed when…)

The nuclear model was developed when alpha scattering showed a small, dense, positively charged nucleus

Describe how the periodic table was arranged by Mendeleev (Mendeleev arranged it by…)

Mendeleev arranged it by atomic mass but left gaps for undiscovered elements

Explain why the modern periodic table uses atomic number (atomic number is used because…)

Atomic number is used because it reflects the number of protons, giving a more accurate arrangement

Describe trends in reactivity of Group 1 (Group 1 reactivity…)

Group 1 reactivity increases down the group because outer electrons are further from the nucleus

Describe trends in reactivity of Group 7 (Group 7 reactivity…)

Group 7 reactivity decreases down the group because atoms gain electrons less easily

Explain displacement reactions in halogens (a halogen displaces when…)

A halogen displaces another when it is more reactive and can gain an electron more readily

Explain why noble gases are unreactive (they are unreactive because…)

They are unreactive because they have full outer electron shells