WEDNESDAY 18TH SEPT - CHEM

• Which subatomic particle was discovered by JJ Thomson?

  Electron
• What is the name of the atomic model proposed by JJ Thomson?

  Plum pudding
• Describe the plum pudding model.

  It is a sphere of positive charge with electrons embedded.
• What did Ernest Rutherford direct at a thin gold leaf in 1905?

  Alpha particles
• What does it indicate when most alpha particles go straight through the gold foil?

  The atom is mostly empty space.
• What did Niels Bohr add to the Rutherford atomic model?

  Electrons orbited the nucleus at specific distances.
• Who discovered the neutron in 1932?

  James Chadwick
• How many times bigger is the atom compared to the nucleus?

  10,000 times
• What is atomic number?

  Number of protons
• What is mass number?

  Number of protons and neutrons in the nucleus
• What are isotopes?


  Atoms that have the same number of protons but different number of neutrons
• In what order were the subatomic particles discovered?

  1. Electrons
  2. Protons
  3. Neutrons
• What are group 1 elements called?

  Alkali metals
• What are group 7 elements called?

  Halogens
• What are group 0 elements called?

  Noble gases
• What is a compound?

  A substance made of two or more elements that are chemically combined in fixed proportions.
• What is an element?


  A substance that is made of only one type of atom.
• What is an ion?


  Charged particles that have either gained or lost electrons.
• Why does the reactivity of group 1 elements increase down the group?

  The number of shells increases, so the outermost electron gets further from the nucleus, decreasing the forces of attraction.
• Why does solid sodium chloride not conduct electricity?

  Because ions are not free to move.
• When does sodium chloride conduct electricity?

  When it is liquid or molten.
• Which ion makes the solution acidic?

  Hydrogen ion (H+)
• Name an indicator that could be used to test if the solution is acidic.

  Universal indicator
• Give the result of the test for acidity using a universal indicator.


  It turns from green to red.
• What type of substance is crude oil?

  Crude oil is a mixture.
• What is crude oil formed of?

  Plankton
• What is a hydrocarbon?

  A hydrocarbon is a molecule made up of carbon and hydrogen only.
• What are the names of the first four alkanes?

  • Methane
  • Ethane
  • Propane
  • Butane
• What is the general formula of alkanes?

  The general formula of alkanes is $C_nH_{2n+2}$.
• State 3 differences between eukaryotic and prokaryotic cells

  Prokaryotic much smaller.

  Prokaryotic do not have a nucleus, single DNA loop free in cytoplasm.

  Prokaryotic cells have a plasmid, eukaryotic cells don't.
• Give an example of eukaryotic and prokaryotic cells

  Eukaryotic = animal and plant cells

  Prokaryotic = bacterial cells
• What organelles do both animal and plant cells have?

  Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes.
• Which part of the cell controls the movement of substances into and out of the cell?

  Cell membrane.
• Which organelle contains the genetic information?

  Nucleus.
• What is the role of the chloroplast?

  Site of photosynthesis.
• Where does aerobic respiration take place?

  Mitochondria.
• What organelles do only plant cells have?

  Chloroplasts, permanent vacuole, cell wall.
• Give 3 examples of animal cells

  Muscle cell, sperm cell, nerve cell.
• Give 3 examples of plant cells

  Root hair cells, companion cells, guard cells.
• Describe 6 differences between a bacterial(prokaryotic) cell and a plant(eukaryotic) cell.

  Bacterial cell is smaller.

  Bacterial cell does not have chloroplast.

  Bacterial cell does not have its DNA in a nucleus.

  Bacterial cells have plasmids.

  Bacterial cell does not have a permanent vacuole.

  Bacterial cells have smaller ribosomes.