A level Definitions Flashcards
Relative Isotopic Mass
The mass of an atom of an isotope compared with 1/12th mass of carbon-12
Relative Atomic Mass (Ar)
The weighted mean mass of an atom of an element compared with 1/12th mass of carbon-12
Isotopes
Atoms of an element with the same number of protons but different number of neutrons.
Molar Mass
Mass per mole units g mol^-1
Mole
The amount of substance 1 mole is 6.02 x 10^23 particles
Acid
Releases H+ ion aqueous solution
Alkali
A soluble base that releases OH- ions in an aqueous solution.
Strong Acid
Fully dissociates in solution
Weak Acid
Partially dissociates in solution
Orbital
A region around the nucleus that can hold up to two electrons, with opposite spins
Disproportionation
Oxidation and reduction of the same element
First Ionisation Energy
The energy needed to remove 1 mole of electrons from 1 mole gaseous of atoms to form one mole of gaseous 1+ ions.
Ionic bonding
The electrostatic attraction between oppositely charged ions. (usually between a metal and non-metal)
Covalent Bonding
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms ( 2 non-metals)
Polar molecule
Compound has polar bonds with dipoles that do not cancel due to their direction
Metallic bonding
The electrostatic attraction between positively charged metal ions and the sea of delocalised electrons.
Electronegativity
the ability of an atom to attract the bonding electrons in a covalent bond
Standard states
physical states under standard conditions
Standard conditions
Temperature: 298 kelvin Pressure: 100 KPa
Enthalpy change of formation
The enthalpy change when one mole of a compound is formed from its elements in their standard states
Enthalpy change of combustion
The enthalpy change for the complete combustion of one mole of a substance