periodic table

• how are elements arranged in the periodic table?

  by atomic number
• why is the periodic table named that?


  elements with similar properties are in certain groups in the period
• why do elements of the same group have similar properties?


  have the same number of electrons in their outermost shell
• how were they arranged before?

  atomic weight
• problems with the early periodic table?

  not all elements discovered

  when placed in terms of atomic weight ended up in the same group
• how did mendeleev solve this problem?

  left gaps for undiscovered elements and changed order of some elements
• what type of ions do metals form?

  positive
• what ion do non metals form?

  negative ions
• where are metals on the periodic table?

  left and bottom
• where are non metals found?

  right and upwards
• what is group 0 known as?

  noble gases
• why are group 0 elements unreactive?


  they have a full outershell - don't need to react with other elements to have a full outer shell
• what happens to boiling point of group 0 as you go down?

  increases down the group
• group 1 are known as?

  alkali metals
• what happens to the reactivity down group 1?

  increases downthe group
• what happens when group 1 reacts with chlorine?

  alkali metal + chlorine = metal chloride
• what happens to group 1 when reacting with water?

  metal + water = metal hydroxide + hydrogen
• elements in group 7 are called?

  halogens
• reactivity what happens down the group?

  it increases
• why are halogens group 7?


  have 7 electrons in their outermost shell
• what colour vapour does chlorine have?

  yellow
• chlorine colour vapour?


  green
• bromine colour vapour?

  red/brown
• iodine colour vapour?

  purple