Foundations in Chemistry Flashcards
Element
a group of atoms which all have the same number of protons
Isotope*
atoms which have the same number of protons but a different number of neutrons
Ion
an atom which has different numbers of protons and electrons causing it be be either positively or negatively charged
Orbital*
a region around the nucleus of an atom that can hold up to two electrons with opposite spins
Relative Atomic Mass*
the weighted mean mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12
Relative Isotopic Mass*
the mass of an atom of an isotope relative to one twelfth of the mass of an atom of carbon-12
Relative Molecular Mass
the mass of a molecule relative to one twelfth of the mass of an atom of carbon-12
Relative Formula Mass
the mass of a formula unit (of a giant structure) relative to one twelfth of the mass of an atom of carbon-12
Molecular Formula
the actual number of atoms of each element in the molecule
Empirical Formula*
the simplest whole number ratio of atoms of each element in the compound
Hydrated
a crystalline compound containing water molecules
Anhydrous
a compound which contains no water molecules
Water of Crystallisation
the water molecules that are combined into the crystalline structure of a hydrated compound
Acid*
a proton donor/produces H+ ions in aqueous solution
Base*
a proton acceptor
Alkali*
a soluble base/produces OH- ions in aqueous solution
Salt*
a compound where the proton in an acid has been replaced by a metal or ammonium ion
Strong Acids*
an acid that completely dissociates in water e.g. HCl, H2SO4, HNO3
Weak Acids*
an acid that partially dissociates in water e.g. carboxylic acids
Oxidising Agent, [O]
a compound which oxidises another compound by gaining electrons and is reduced
Reducing Agent, [H]
a compound which reduces another compound by losing electrons and is oxidised
Ionic Bonding*
the strong electrostatic attraction between oppositely charged ions
Metallic Bonding*
the strong electrostatic attraction between positive metal ions and the sea of delocalised electrons
Covalent Bond*
the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
Dative Covalent Bond*
a covalent bond where both electrons are donated by one of the atoms
Hydrogen Bond*
a strong dipole-dipole attraction between an electron deficient hydrogen atom of -NH, -OH or -HF and a lone pair of electrons on a highly electronegative atom containing O, N, or F in a neighbouring molecule
Electronegativity*
the ability of an atom to attract the electrons in a covalent bond
Dipole/Polar Bond/Polar Molecule
a covalent bond or molecule where the electron density is shifted more towards one end than the other
Permanent Dipole*
a small charge difference across a bond that results from a difference in the electronegativities of the bonded atoms
