periodic table

• the elements in the table are arranged in order of what

  in order of atomic number
• what does the group(columns) number tell you

  number of electrons in the outer shell
• what does the period number (rows) tell you

  number of shells occupied by electrons
• why do elements in the same group have similar propterties

  same number of electrons in the outer shell - similar reactivity - similar propterties
• describe the periodic table before discovery of subatomic particles

  • scientists attempted to classify the elements by arranging them in order of their atomic weights
  • they were incomplete and some elements were placed in inappropriate groups if the strict order of atomic weights was followed
• how did mendeleev change the table

  • by leaving gaps for elements that he thought had not been discovered and in some places changed the order based on atomic weights
  • Elements with properties predicted by Mendeleev were discovered and filled the gaps
• what can we use to explain why order based on atomic weight wasnt always correct

  knowledge of isotopes
• where are metals and non-metals found on the periodic table

  metals = bottom left

  non-metal = top right
• what type of ions do metal and non-metals form

  metal = positive

  non-metal = negative
• properties of metals

  shiny and silver

  high melting/boiling point

  conduct electricity and heat

  high density

  strong

  solid at room temp

  malleable and ductile
• properties of non-metals

  dull

  low melting/boiling point

  do not conduct electricity and heat

  low density

  not strong

  often gas at room temp

  brittle and soft
• which group are the noble gasses

  group 0
• why are noble gasses unreactive

  unreactive and do not easily form molecules because their atoms have stable arrangements of electrons
• describe the boiling point of noble gasses

  increases as you go down - atoms get bigger - stronger forces
• describe nature of group 0 at room temo

  non-metal , colourless gas
• describe group 1

  • alkali metals
  • forms ionic compounds
  • highly reactive
  • low density and soft
  • melting/boiling point decrease as you go down
  • 1 electron in outer shell
• why do group 1 get more reactive as you go down

  • distance from electron and protons increase
  • forces of attraction get weaker
  • easier to lose electron
• describe the reaction on an alkali metal with oxygen

  metal + oxygen - metal oxide
• describe the reaction on an alkali metal with chlorine

  metal + chlorine - metal chloride

  • bright light
  • formation of white solid
• describe the reaction of an alkali metal with water

  • metal + water - metal hydroxide(alkaline) + hydrogen
  • metal will float
  • there will be bubbles
  • metal will move around
• what are the halogens

  group 7 , non metals
• which group is diatomic

  the halogens
• what properties increase as you go down the halogens

  • melting point
  • boiling point
  • relative molecular mass
• what decreases as you go down the halogens and hwy

  the reactivity- electron and protons further - weak forces of attraction - harder to gain an electron
• what happens when a halogen reacts with non-metals

  form covalent compounds
• what happens when halogens react with metals

  • form ionic compounds
  • form hailde/salt ions with a -1 charge and a positive metal ion
• describe when halogens can displace each other

  a more reactive halogen can displace a less reactive halogen from an aqueous solution of its salt
• compare transition metals to group 1 metals

  • higher melting/boiling
  • higher density
  • stronger and harder
  • less reactive
• two typical properties of transition metals

  • form ions with different charges
  • form colorful compounds