Unit 1 chemistry- Key definitions

A list of all the key definitions for the Unit 1 - foundation chemistry paper

HideShow resource information
  • Created by: beckie
  • Created on: 24-02-12 20:00
Preview of Unit 1 chemistry- Key definitions

First 436 words of the document:

Chemistry Unit 1- Key definitions
Atomic number- the number of protons in the nucleus
Mass number- the number of protons and neutrons in the nucleus
Relative atomic mass- the average mass of an atom/ 1/12th mass of 1 atom of carbon 12
Relative molecular mass- the average mass of an / 1/12th mass of 1 atom of carbon 12
Isotopes- atoms with the same number of protons but a different number of neutrons
First ionisation energy- the enthalpy change when one mole of gaseous atoms forms one
mole of gaseous ions with a single charge
Second ionisation energy- the enthalpy change when one mole of gaseous ions with a
single positive charge forms one mole of gaseous ions with a double positive charge
Electronegativity- the relative tendency of an atom in a covalent bond in a molecule to
attract electrons the covalent bond itself
Covalent bonding- a covalent bond is a shared pair of electrons
Ionic bonding- a ionic bond it the electrostatic force of attraction between oppositely
charges ions formed by electron transfer
Metallic bonding- a metallic bond is the electrostatic force of attraction between the
positive metal ions and the sea of delocalised electrons
Empirical formula- the simplest whole number ratio of atoms of each element in a
compound
Molecular formula- the actual number of atoms of each type of element in a compound
Structural formula- shows all the covalent bonds in a compound
Displayed formula - the drawn out version of the structural formula
Homologous series- families of organic compounds with the same functional group ,
general formula, chemical properties, each member differs by CH2 and they show a
gradual change in physical properties
Functional group- an atom or group of atoms which when present in different molecules
causes them to have similar chemical properties
Structural isomers- same molecular formula but a different structural formula
Chain isomers- compounds with the same molecular formula but a different structure of
the carbon skeleton.
Positional isomers- same molecular formula but different position of the same functional
group on the same carbon skeleton
Function group isomers- same molecular formula but a different functional group
Hydrocarbon- a compound consisting of carbon and hydrogen atoms
Saturated- contains single carbon-carbon bonds only
Petroleum fraction- mixture of hydrocarbons with a similar chain length and boiling range
Cracking- the conversion of large hydrocarbons to smaller molecules by breakage of the
c-c bonds
Fuel- Releases heat energy when burnt

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »