definitions

• Ammonium ion: an ion with the formula NH 4 +
• Carbonate: an ion with the formula CO 3 2 -
• Trigonal bi pyramidal: the shape of a molecule in which the central atom has 5 bonding pairs.
• Trigonal Planar: the shape of a molecule in which the central atom has 3 bonding pairs.
• Hydroxide: an ion with the formula OH -
• Ionic Compound: a compound which is made up of oppositely charged ions that are held together by electrostatic forces
• Nitrate: an ion with the formula NO 3 -
• Silver ion: has the formula Ag +
• State symbols: symbols within a chemical equation which indicate the state of each compound under the reaction conditions
• Atomic Orbital: a region of space around the nucleus that can hold up to 2 electrons with opposite spins
• There is 1 orbital in the s subshell, 3 orbitals in the p subshell and 5 orbitals in the d subshell
• Orbitals are filled in order of increasing energy, with orbitals of the same energy occupied singly before pairing
• Electronic Configuration: the arrangement of electrons into orbitals and energy levels around the nucleus of an atom / ion
• Energy Level: the shell that an electron is in
• Shell: the orbit that an orbital is in around the nucleus of an atom.
• The shell closest to the nucleus is the first shell
• The outermost shell that is occupied by electrons is the valence shell
• Sub-shell: a subdivision of the electronic shells into different orbitals.
• The types of subshell are s, p, d and f.
• Permanent Dipole: a permanent uneven distribution of charge.
• Types of intermolecular forces including permanent dipole - dipole interactions and induced dipole - dipole interactions (both of these are also known as van der Waals’ forces) as well as hydrogen bonding.
• Molecular substances don’t conduct electricity.
• Ionic Bond: electrostatic attraction between positive and negative ions.
• Hydrogen Bonding: a type of intermolecular bonding that occurs between molecules containing N, O or F and a H atom of - NH, - OH or HF.
• Tetrahedral: the shape of a molecule in which the central atom has 4 bonding pairs.
• Lone pairs offer more repulsion than bonding pairs as they are closer to the nucleus of the central atom.
• Polar Bond: a covalent bond that has a permanent dipole due to the different electronegativities of the atoms that make up the bond.
• Ionic Lattice: a giant structure in which oppositely charged ions are strongly attracted in all directions.
• Electron Pair Repulsion Theory: pairs of electrons around a nucleus repel each other so the shape that a molecule adopts has these pairs of electrons positioned as far apart as possible.
• Ionic compounds are soluble and can conduct electricity when liquid or aqueous (but not when solid).
• Macroscopic Properties: properties of a bulk material rather than the individual atoms/ molecules that make up the material.
• Intermolecular Forces: interactions between different molecules.
• Non-linear: the shape of a molecule in which the central atom has 2 bonding pairs and 2 lone pairs.
• Pyramidal: the shape of a molecule in which the central atom has 3 bonding pairs and 1 lone pair.
• Lone Pair: a pair of outer-shell electrons not involved in bonding.
• Polar Molecule: a molecule that contains polar bonds with dipoles that don’t cancel out due to their direction (must be unsymmetrical).
• Linear: the shape of a molecule in which the central atom has 2 bonding pairs.
• Simple Molecular Lattice: a solid structure made up of covalently bonded molecules attracted by intermolecular force (e.g. I2 and ice).
• London (Dispersion) Forces: induced dipole - dipole interactions caused when the random movement of electrons creates a temporary dipole in one molecule which then induces a dipole in a neighbouring molecule.
• Octahedral: the shape of a molecule in which the central atom has 6 bonding pairs.