chemistry paper 1

• what is an an atom

  nucleus, electrons, protons and neutrons
• complete the sentences

  in the centre of the atom there is a nucleus. the nucleus is made up of protons and neutrons. around the nucleus there are particles called electrons
• name the particle and the mass and the charge

  proton mass : 1 charge: +1 neutron mass : 1 charge: 0 electron mass: 0 charge: -1
• atoms have no overall charge, explain in terms of sub-atomic particles

  there are qual number of positive protons and negative charges to cancel out
• what does the atomic number of an element tell us

  number of protons
• what does the mass number of an element tell us

  the number of protons and neutrons
• which sub- atomic particles defines which element an atom belongs to

  proton
• what is an isotope

  same number of protons but different number of neutrons
• describe, in terms of electrons, what happens when a magnesium atom reacts with chlorine atoms to produce magnesium chloride

  each magnesium atom looses 2 electrons w chlorine atoms. each gain 1 electron to complete their outer shells
• put the metals in order of reactivity from the most reactive to least reactive

  most: potassium, sodium, lithium, calcium, magnesium, zinc, iron, copper :least
• why does gold not need to be extracted from ores

  its so unreactive
• iron can be extracted rom an ore. what is an ore

  compound from which a metal can be extracted for profit
• explain why calcium cannot be extracted by heating calcium chloride with carbon

  calcium is more reactive than carbon
• explain why this extraction involves a reduction reaction

  calcium gains electrons
• what is the reaction called when oxygen is lost

  reduction
• how would you calculate the percentage mass

  % mass = mass of element / mass of compound * 100
• calculate the mean

  add all the values then divide by how many there are
• what is endothermic

  heat energy is going in
• what is exothermic

  heat is giving out
• examples of exothermic reactions

  burning fuels, most neutralisation reactions, displacement reactions, reactions of metals with acids
• examples of endothermic reactions

  decomposition reactions, reactions, of acids with hydrogen carbonates
• examples of exothermic reactions in everyday life

  burning fuels, hand warmers, self heating cans
• examples of exothermic reaction in everyday life

  sports injury ice packs, sherbet contains acid & sodium hydrogen carbonate
• what name is given to the elements in group 1

  alkali metals
• what name is given to the elements in group 7

  halogens
• explain why diamond is very hard

  each carbon is bonded to 4 other carbons in a rigid 3D structure
• explain why graphite can conduct electricity

  it has delocalised electrons which can move through the structure and carry the charge
• give one use of fullerenes

  lubricant
• What did James Chadwick make

  neutron
• Mendeleev: what he do to the periodic table 


  left gaps, groups according to how there reactivity. early periodic table- ordered by atomic weight. new periodic table- proton number
• describe the reading trend for group 1

  it is more reactive as you go down the group
• why is an atom neutral in charge

  same number of electrons and protons
• metals always form positive ions. non metals always form negative ions
• giant covalent bonds: diamond

  Hard. Strong covalent it does not conduct. 4 strong bonds so no free electrons
• giant covalent bonds: graphite

  does conduct 3 strong bonds so it has 3 free electrons. lubricant/ slippery- layers slide