1/2/3 markers

• what is an isotope?

  atom with the same number of protons but a different number of neutrons
• what is an element?

  a substance made of one type of atom/ same types of protons and cant be broken down into smaller pieces
• what is a compound?


  A compound is a substance made up of two or more different elements chemically bonded together.
• what is a mixture?


  A combination of two or more substances that are not chemically bonded.
• what is the name of group 1?

  Alkali metals
• what is the name of group 2?

  Alkaline Earth Metals
• what is the name of ggroup 3?

  Transition metals
• what is the name of group 4?

  Carbon
• what is the name of group 6?

  Chalcogens
• what is the nameof group 7?

  Halogens
• what is the name of group 8?

  noble gases
• what is thename of group 0?

  Noble gases
• properties of alkali metals?


  Reactivity, softness, low melting points form +1 ions
• properties of transition metals?


  Ductile, malleable, good conductors of heat and electricity, form colored compounds. used aas catalysts and form ions with different charges
• properties of halogens?


  Reactivity, high electronegativity, diatomic molecules.
• properties of noble gases?


  Inert, colorless, odorless, and nonflammable.
• trends in alkali metals as it goes down?

  • Reactivity increases because the outer electron in each atom is further away from the nucleus as you go down the group and so the electrostatic forces between the nucleus and the outer electron are weaker.
  • Lower melting and boiling points
  • higher ddensity
• trends of halogens as it goes down?

  • The melting points and boiling points of the halogens increase as you go down the group. This is because larger molecules within the same group experience greater intermolecular interactions with each-other, & more energy is required to overcome the interactions between neighbouring atoms.
  • less reactive as its harder to gain an extra electron since the outer shell is further away from the nucleus
  • higher rleative atomic mass
• trends of noble gases as it goes down?

  • boiling point increases since there is an increase in the number of electrons in the atom leading to greater intermolecular forced needed to overcome
  • increasing relative atomic mass
  • inert
• two reasons why the discovery of gallium helped mendeleevs periodic table get accepted?

  • fit in with the gap left by mendeleev
  • properties were predicted properly/fit in with the rest of the group
• three differences between the nuclear vs plum pudding model?

  • (nuclear) is mostly empty space whereas plum pudding is solid and has no empty space
  • (nuclear) has all positive charge in the nucleus whereas the plum pudding is a ball of positive charge
  • (nuclear) mass is concentrated in te nucleus whereas in plum pudding it is spread out
• describe the change Bohr added to hte nuclear model?

  electrons orbit the nucleus in shells at fixed distances
• why did mendeleev reverse the order of some pairs in the table?

  so they matched the properties to the rest of their group
• how does distillation produce pure water from a salt solution?

  1. solution is heated
  2. water evaporates
  3. vapour cools in the condenser then condenses
  4. vapour turned into liquid
  5. pure water collects in the beaker
• explain alpha particle scattering experiment?

  • most alpha particles passed straight through the goldfoil sine the atom is mostly empty space/ is concentrated in the nucleus
  • some alpha particles had deflected so it showed the nucleus had a positive charge therefore protons in the nucleus
• describe how james chadwicks work led to understanding of isotopes?

  • Chadwick discovered neutrons
  • which is necessary since isotopes have the same number of protons but different number of electrons
• what is a pure substance?

  A substance that is made up of only one type of particle or molecule.
• how do observations show am increase in reactivity?

  • increase in speed of movement
  • increased rate of bubble production
  • flame -> explosion
• two observations when potassium is added to water?

  1. effervescence
  2. melts/ becomes smaller while floating around
• why does sodium oxide have a high melting point?

  • giant structure
  • strong electrostatic forces of attraction between oppositely charged ions
  • large amounts of energy needed to overcome the bonds
• why did mendeleevs periodic table become widely accepted rather than previous versions?

  • mendeleev had predicted properties of unknown/missing elements
  • elements were discovered that fit into the missing gaps
  • their properties matched mendeleevs predictions
• why can carbon be used for extraction via reduction?

  carbon is more reactive so displaces
• why is chlorine more reactive than iodine?

  • chlorines outer electrons on shell are closer to the nucleus
  • which increases attraction of nucleus
  • chlorine gains electron easier
• explain why certain mixtures are gas at room temperatures?

  • made of small molecules
  • with weak intermolecular forces
  • dont need a lot of energy to break bonds
• explain how observations show silver is less reactive that copper?

  grey crystals are silver copper produces blue ions, copper displaces silver
• limitation of using a dot and cross diagram?

  2 dimensional and doesnt show the true shape
• explain why reaction is performed in argon and not air?

  argon is inert, oxygen from the air would react
• how is carbon monoxide produced in car engines?

  incomplete combustion due to insufficient amount of oxygen supply
• two reasons why maximum amount of carbon monoxide percentage has decreased for newer cars?

  • carbon monoxide is poisonous/ toxic
  • greater public has shown concern
  • improved engine technology
  • catalyctic converters introduced
• one reason of needed decrease in hydrocarbons?

  decrease global dimming