Atomic Structure

Cards (33)

  • element is a substance made from one type of atom
  • compound is a substance made up of two or more different types of atoms joined together by chemical bonds.
  • the total mass of the product formed in a reaction is equal to the total mass of the reactants
  • the subatomic particles are protons , neutrons and electrons
  • same number of protons and electrons
  • electrons orbit the nucleus on energy shells at fixed distances
  • relative atomic mass = protons and neutrons
  • atomic number = number of protons
  • neutrons = relative atomic mass-atomic number
  • protons have a relative charge of +1 (positive)
  • neutrons have a relative charge of 0 (neutral)
  • electrons have a relative charge of -1 (negative)
  • proton has a mass of 1
  • neutrons have a mass of 1
  • electrons are very small (1/2000)
  • atoms are neutral because the number of protons and electrons are the same so they cancel each other out and neutrons have no charge so it makes no difference.
  • 1st shell= 2 electrons 2nd shell= 8 electrons 3rd shell= 8 electrons 4th shell= 18 electrons
  • group number tells u the number of electrons on the outer shell of an atom
  • noble gases (group 0) are non-metals and have full outer shells
  • radius of an atom is approximately 0.1nm
  • an ion is an atom that has gained or lost and electron
  • loosing an electron makes the ion positive
  • isotopes are atoms of the same element with a different amount of neutrons in the nucleus
  • gaining an electron makes an ion negative
  • different isotopes have different chemical properties e.g different densities or radioactive
  • plum pudding model- sphere of positive charge embedded with negatively charged electrons,no empty spaces,mass evenly distributed by J.J Thomson
    • Nuclear model- densely packed positively charged nucleus, negatively charged electrons orbit the nucleus,most of the mass is concentrated at the nucleus,majority empty space by Rutherford
  • Gold foil experiment - Positively charged alpha particles were fired at a thin sheet of gold foil.Majority of the alpha particles passed through but 1 in 10000 were deflected.This proved that the atom had a dense positive nucleus that was tiny in the centre of the atom.
  • electrons were discovered first , then protons and then neutrons.
  • a mixture is a substance that contains two or more elements or compounds that are not chemically combined
  • filtration-separate an insoluble solid from a liquid.The residue is left in the filter paper and the liquid that travels through is known as the filtrate
  • crystallisation/evaporation-separates the soluble solid from a liquid ,the liquid evaporates leaving the solid behind
  • distillation-separates a soluble solid from a liquid but the liquid is retrieved.The condenser cools down the liquid.