GCSE Chemistry Chemical Bonding Flashcards

Vocabulary flashcards defining key concepts, structures, and properties of ionic, covalent, and metallic bonding.

Ionic bonding

The electrostatic attraction between oppositely charged ions (formed by the transfer of electrons from metal to non-metal)

Ion formation in ionic bonding

Metals lose electrons to form positive ions (cations); non-metals gain electrons to form negative ions (anions)

Cation

A positively charged ion (formed when an atom loses electrons)

Anion

A negatively charged ion (formed when an atom gains electrons)

Giant ionic lattice

A regular arrangement of alternating positive and negative ions held by strong electrostatic forces

Melting and boiling points of ionic compounds

High, because strong electrostatic forces between ions require a lot of energy to overcome

Electrical conductivity of ionic compounds

Ionic compounds conduct electricity when molten or dissolved because ions are free to move, but do not conduct when solid because ions are fixed in the lattice

Covalent bonding

The sharing of one or more pairs of electrons between non-metal atoms so that each atom achieves a full outer shell

Single covalent bond

One shared pair of electrons between two atoms

Double covalent bond

Two shared pairs of electrons between two atoms

Triple covalent bond

Three shared pairs of electrons between two atoms

Simple molecular substance structure

Small molecules held together by strong covalent bonds within the molecule, but weak intermolecular forces between molecules

Melting and boiling points of simple molecular substances

Low, because weak intermolecular forces between molecules require little energy to overcome

Electrical conductivity of simple molecular substances

They do not conduct electricity because there are no free ions or delocalised electrons to carry charge

Giant covalent structure

A huge network of atoms joined by strong covalent bonds throughout the structure (e.g. diamond, graphite, silicon dioxide)

Melting point of giant covalent structures

Very high, because many strong covalent bonds must be broken to melt the substance

Diamond properties

Very hard; does not conduct electricity (no free electrons)

Graphite properties

Soft/slippery (layers can slide); conducts electricity (delocalised electrons between layers)

Metallic bonding

The electrostatic attraction between a lattice of positive metal ions and a 'sea' of delocalised electrons

Electrical and thermal conductivity of metals

Metals conduct electricity and heat because delocalised electrons are free to move and carry charge / energy

Malleability and ductility of metals

Layers of metal ions can slide over each other while the delocalised electrons continue to hold the structure together

Difference between ionic and covalent bonding

Ionic = electron transfer (metal + non-metal); covalent = electron sharing (non-metal + non-metal)

Bonding types involving delocalised electrons

Metallic bonding (and also graphite)

Three main types of strong chemical bonding

Ionic, covalent and metallic

Determinants of substance properties

Both the type of bonding and the overall structure (giant or simple)

Formula of an ionic compound

Worked out by balancing the charges so the total positive charge equals the total negative charge

Intermolecular force

A weak force of attraction between molecules (not the strong covalent bonds within molecules)

Hardness comparison between graphite and diamond

Graphite has layers held by weak forces that can slide; diamond has a rigid 3D network of strong bonds

Electrons in metallic bonding

Outer electrons become delocalised and free to move throughout the metal lattice

Examples of structural types

Ionic lattice: sodium chloride; Simple molecular: water/methane; Giant covalent: diamond/graphite; Metallic: copper/iron