the periodic table

• What discovery allowed scientists to understand similar chemical properties in elements?

  The discovery of electrons
• How do elements with the same number of electrons in their outer shell behave?

  They have similar chemical properties
• What did the discovery of protons enable scientists to do?

  Order elements by atomic number
• What did the discovery of neutrons lead to?

  Discovery of isotopes
• Why did some elements not fit when organized by atomic mass?

  Isotopes explained the discrepancies
• What are elements in group 0 called?

  Noble gases
• What are the properties of noble gases?

  • Full outer shells
  • Very unreactive (inert)
  • Exist as single atoms
  • Boiling points increase down the group
• What do group 1 elements react with?

  Oxygen, chlorine, and water
• What is formed when lithium reacts with oxygen?

  Lithium oxide
• What is produced when lithium reacts with water?

  Lithium hydroxide and hydrogen
• Why are group 1 elements called alkali metals?

  They react with water to form an alkali
• What are the properties of group 1 elements?

  • One electron in outer shell
  • Very reactive
  • Reactivity increases down the group
  • Melting point decreases down the group
• Why do group 1 elements become more reactive down the group?

  Atoms increase in size and shielding increases
• What happens to the electrostatic force of attraction in group 1 elements down the group?

  It becomes weaker
• What are group 7 elements called?

  Halogens
• What are the properties of halogens?

  • Non-metals
  • Exist as molecules of pairs of atoms
  • Melting and boiling points increase down the group
  • Reactivity decreases down the group
• Why does reactivity decrease down group 7?

  Atoms increase in size and shielding increases
• What is the effect of distance on the electrostatic attraction in group 7 elements?

  It becomes weaker as distance increases
• What is displacement in group 7 elements?

  More reactive elements replace less reactive ones
• What is produced when fluorine reacts with potassium chloride?

  Potassium fluoride and chlorine
• What did the discovery of electrons allow scientists to do?

  Work out that elements with the same number of electrons in their outer shell have similar chemical properties
• What did the discovery of protons allow scientists to do?

  Order the elements in the periodic table by their atomic number
• What are elements in group 0 called?

  Noble gases
• What did the discovery of neutrons lead to?

  The discovery of isotopes
• Why do noble gases not need to gain or lose electrons?

  They have full outer shells
• Why do noble gases exist as single atoms?

  They are very unreactive (inert) and do not bond to form molecules
• What happens to the boiling points of noble gases as you go down the group?

  They increase
• What do group 1 elements react with?

  Oxygen, chlorine, and water
• What are the products when lithium reacts with oxygen, chlorine, and water?

  Lithium oxide, lithium chloride, and lithium hydroxide + hydrogen
• Why are group 1 elements called alkali metals?

  They react with water to form an alkali
• What do group 1 elements have in common?

  They all have one electron in their outer shell
• Why are group 1 elements so reactive?

  They only need to lose one electron to react
• Why does the reactivity of group 1 elements increase down the group?

  Because the atoms increase in size, the outer electron is further from the nucleus, and the electrostatic force of attraction is weaker
• What happens to the melting point of group 1 elements as you go down the group?

  It decreases
• What are group 7 elements called?

  Halogens
• What is the physical state of group 7 elements?

  They exist as molecules made up of pairs of atoms
• What happens to the melting and boiling points of group 7 elements as you go down the group?

  They increase
• Why does the reactivity of group 7 elements decrease down the group?

  Because the atoms increase in size, the outer shell is further from the nucleus, and the electrostatic attraction is weaker, making it harder to gain the one electron needed to fill the outer shell
• What is displacement in group 7 elements?

  More reactive group 7 elements can take the place of less reactive ones in a compound
• What are the key properties of the noble gases (group 0)?

  • Have full outer shells, so do not need to gain or lose electrons
  • Very unreactive (inert), so exist as single atoms and do not bond to form molecules
  • Boiling points increase down the group