Chemistry

• what are compounds

  atoms of different elements combined together
• how many types of element does a compound have to contain

  at least 2 different elements
• what are the key features of a chemical reaction (there are 4)

  compounds broken or formed, at least 1 new substance, measurable energy change, no atoms created or destroyed
• what side of a chemical equations are the reactants

  left hand side
• what side of the chemical equation are the products

  right hand side
• what did John dalton first suggest in 1803

  all matter is made of atoms and that atoms cannot be split
• what did J.J Thomson discover in 1897

  electrons
• what model did J.J Thomson create after his discovery of electrons in 1897

  plum pudding model
• what was J.J Thomsons plum pudding model of the atom

  a ball of positive charge with negatively charged electrons mixed in
• what did Ernest Rutherford discover with his gold foil experiment in 1909

  that alpha particles could bounce back off atoms
• what did Ernest Rutherford conclude from his gold foil experiment

  that an atoms mass was concentrated in its centre. he called this centre the nucleus and it contained positively charged particles called protons
• how did Niels Bohr contribute to the modern atom model

  discovered that electrons orbit the nucleus at fixed distances
• how did James Chadwick contribute to the modern atom model

  discovered some particles in nucleus have no charge at all - called neutrons
• what are the three different sub atomic particles

  protons, electrons and neutrons
• why does an atom have no overall charge

  the charges of the subatomic particles cancel each other out
• what charge does a proton have

  +1
• where are protons found

  in the nucleus of an atom
• what is the relative atomic mass of a proton

  1
• what is an elements atomic number

  number of protons it possesses
• what will all atoms of the same element possess

  same number of protons
• what is the relative charge of a electron

  -1
• where are electrons found in the atom

  orbiting around the nucleus at fixed distances
• what is the relative atomic mass of electron

  1/2000 which we approximate to 0
• what does the number of electrons in an atom also equal to

  number of protons
• why does the number of protons and electrons cause and atom to have no overall charge

  same number of positive protons and negative electrons cancel each other out
• what is the relative charge of a neutron

  0, they are neutral
• where are neutrons found

  the nucleus
• what is the relative atomic mass of a neutron

  1
• why does an atoms neutron number not affect the atoms charge

  neutrons have no charge so do not affect it
• approximately what is the size of the radius of an atom

  0.1 nanometres, or 1x10^-10 m
• what is the relative mass of an atom

  the number of protons + neutrons
• what are isotopes

  atoms of the same element that have the same number of protons but have a different number of neutrons
• what are the 3 isotopes of hydrogen

  protium, deuterium and tritium
• what is the most common isotopes of hydrogen

  protium - approx 99.98% of hydrogen atoms are protium
• what is protium used for

  fuel cells and production of plastics
• approximately how many hydrogen atoms are deuterium

  0.02%
• what is deuterium used for

  nuclear fusion
• what is tritium used for

  thermonuclear fusion weapons
• what is a nuclide

  a type of isotopes. refers to a specific nucleus that contains a certain number of protons and neutrons
• what is the relative atomic mass (Ar)

  average mass of all the isotopes of an element. takes into account how often each isotopes is found (isotope abundance)