atomic structure +amount of substance

• What is stated in Daltons theory?

  • Atoms are small particles
  • atoms can not be divided
  • all atoms in an element are the same
  • atoms of one element are different to those of other elements
• What did Thompson discover about electrons?

  • they have a negative charge
  • they can be deflected by magnet and electric field
  • they have very small mass
• Explain plum pudding model 


  atoms are made up of negative electrons moving around in a sea of positive charge
• What were Rutherford proposal after the gold leaf experiment?

  • mass and positive charge are in the nucleus
  • electrons orbit nucleus
  • overall positive and negative charge must balance
• Explain the current model of atom

  • protons and neutrons are in the nucleus
  • electrons orbit in shells
  • mass = neutrons + protons
• Charge of a proton 


  1+
• Charge of an electron

  1-
• what particle has the same mass as a proton


  neutron
• which two particles make up the mass of an atom

  neutron and proton
• Which letter is used to represent the atomic number of an atom

  z
• what does the atomic number tell us?

  atomic number = number of protons in an atom
• which letter represent the mass number

  A
• how is mass number calculated

  protons + neutrons = mass number
• define isotope 


  atoms of the same element but with a different number of neutrons
• Why does different isotopes of the same element react in the same way?

  • Because isotopes of the same element have the same number of protons and electrons, which determines their chemical behaviour
  • neutrons do not effect chemical reactivity
• what are ions?


  charged particles that are formed when an atom gains or loses electrons
• what is the charge of an ions when an electron is gained?


  negative
• define relative atomic mass


  the weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12
• define relative isotopic mass 


  the mass of an atom of an isotope compared with with one twelfth of the mass of an atom of carbon-12
• the relative isotopic mass is the same as which number?

  mass number
• what are the uses of mass spectrometry?

  • used to identify the unknown
  • find relative abundances of each elements isotopes
• how is group number related to the number of electrons

  group number = number of electrons in outer shell
• do metals usually loose or gain electrons

  lose electrons
• what are molecular ions 


  covalently bonded atoms that lose or gain electrons
• what is the charge of ammonium

  NH4+
• what is the charge of a hydroxide ion

  OH-
• what is a nitrate ion

  NO3-
• what is a carbonate ion 


  CO3 2-
• what is a sulphate ion 


  SO4 2-
• what is empirical formula

  simplest whole number ratio of atoms of each element present in a compound
• how to calculate empirical formula

  • divide the amount of each element by its molar mass
  • divide the answer by the smallest value obtained
  • if there is a decimal, divide by a suitable number to make it into a whole number
• what is avogardos constant

  6.02 * 10 23 particles
• water of crystallisation 


  water that is part of crystalline structure. hydrated substances contain them.
• what does Avogadro's constant represent 


  the number of atoms per mole of carbon-12 isotope
• ideal gas equation 


  Pv=nRT
• what is the atmospheric pressure equivalent to in pascal?

  101pa
• what is 0 degrees in kelvin

  273K