Atoms ions and compounds

• What charge does a neutron have?

  0
• In what year did John Dalton propose the billiard ball model?

  1803
• According to Dalton's model, what are atoms?


  Tiny particles that make up elements
• In what year did Rutherford, Geiger, and Marsden conduct their experiment?

  1909
• What charge does a proton have?

  +1
• What charge does an electron have?

  -1
• According to Dalton, can elements be split any further?

  No
• In what year did Bohr work out electron shells?

  1913
• In what year did Rutherford discover protons?

  1918
• In what year did Chadwick discover the neutron?

  1932
• What does the relative atomic mass (Ar) of an element compare to?

  Mass of one atom to 1/12 of carbon-12
• Relative atomic mass is often calculated using what?

  Isotope percentages
• Radium has two isotopes, one with a mass of 8 and another with a mass of 9; if their relative abundance is 0.1215, what is their percentage abundance?

  12.15%
• What is the relative molecular mass (Mr) of an element or compound?

  Mass relative to 1/12 of one carbon-12
• What is a molecule?

  Simplest unit of a compound
• What is another term for relative molecular mass?

  Relative formula mass
• How is relative formula mass calculated?

  Sum of Ar values of atoms
• What are the steps to calculate relative formula mass?

  • Count the number of atoms.
  • Substitute the Ar values.
  • Add the values together.
• What does the mass spectrum show?

  Relative abundance
• What is relative abundance equal to?

  Percentage abundance
• What is an element?

  A substance of one type of atom
• Why is the overall charge of a molecule considered when describing molecular ions?

  Because the electrons aren't shared with the entire molecule
• Which elements commonly have variable valence charges?

  Transition metals
• What is the formula for Iron (II) ion?

  $Fe^{2+}$
• What is the formula for Iron (III) ion?

  $Fe^{3+}$
• What force holds ionic compounds together?

  Electrostatic attraction
• What are ionic compounds made of?

  Metal and non-metal
• How can the formula of ionic compounds be determined?

  From the constituent ions' charges
• What can cause variable valence charges?

  Post modifications