Non-metalsThey are elements that lack most of the properties of metals Physical Properties Chemical Properties • Have lower density. • Most of them are • Powder, stones, reactive. liquids, or gases. • Their atoms usually • Poor conductors of gain or share heat and electricity. electrons during • 10 of 16 non-metals chemical reaction. are gases at room • Can form covalent temperature. compounds with other non-metals.
Group 18 – The Noble gasesSome facts…1) All of the noble gases havea full outer shell, so they arevery Unreactive.2) They all have low melting and boiling points3) They exist as single atoms rather then diatomic molecules3) Helium is lighter than air and is used in balloonsand airships (as well as for talking in a silly voice)
Group 13: Boron GroupAluminum is the most common elementfrom Group 13. Group 13 properties:• group contains one metalloid and fivemetals• 3 electrons in the outer level• reactive• solids at room temperature
Group 14: Carbon GroupGroup 14 properties:• group contains one nonmetal, twometalloids, and two metals• 4 electrons in the outer level• reactivity varies among the elements• solids at room temperature•Example: Diamonds and soft are carbon•Example: Silicon and Germanium makecomputer chips
Group 15: Nitrogen GroupGroup 15 properties:• group contains two nonmetals, twometalloids, and two metals• 5 electrons in the outer level• reactivity varies among the elements• solids at room temperature (except fornitrogen, which is a gas)
Group 16: Oxygen GroupGroup 16 properties:• group contains three nonmetals, onemetalloids, and one metal• 6 electrons in the outer level• reactive• solids at room temperature (except foroxygen, which is a gas)•Example: Sulfur is the most widely usedelement in the chemical industry•Example: Oxygen makes up about 20% ofthe atmosphere and is needed to burn
Group 7 – The HalogensSome facts… reactivity Decreasing1) Reactivity DECREASESas you go down the group(This is because the electrons are further away from thenucleus and so any extra electrons aren’t attracted as much).2) They exist asdiatomic molecules (sothat they both have a Cl Clfull outer shell):3) Because of this fluorine and chlorine are gases at roomtemperature and bromine is a water
1) Halogen + metal: The halogens – some reactions + - Na + Cl Na Cl Halogen + metal ionic salt2) non-metal + halogen: H + Cl Cl H Halogen + non-metal covalent molecule
Uses of the Halogens• Fluorine is put into water supplies to kill harmful bacteria and to help keep teeth healthy.• Chlorine is used in swimming pools to kill bacteria in the water.• Bromine is used in pesticides. Silver bromide is used in photography.• Iodine is an antiseptic on cuts and grazes.
Metalloids•Metalloids are the elements that border thezigzag line. Atoms of metalloids have abouthalf of a complete set of electrons in theirouter energy level.• Metalloids have some properties of metalsand some properties of nonmetals.• Metalloids are also called semiconductors.
How shells fill• The first electron shell can only hold a maximum of 2 electrons.• The second electron shell can hold a maximum of 8 electrons.• The third electron shell can also hold a maximum of 8 electrons.• The fourth electron shell can also hold 8 electrons.
Electron structureConsider an atom of Potassium: Nucleus Potassium has 19 electrons. These are arranged in shells…The inner shell has __ electronsThe next shell has __ electronsThe next shell has __ electrons Electron structureThe next shell has the remaining __ electron = 2,8,8,1
First 20 Elements continued• Hydrogen 1• Helium 2• Lithium 2,1• Beryllium 2,2• Boron 2,3• Carbon 2,4• Nitrogen 2,5
First 20 Elements continued• Oxygen 2,6• Fluorine 2,7• Neon 2,8• Sodium 2,8,1• Magnesium 2,8,2• Aluminum 2,8,3• Silicon 2,8,4
First 20 Elements continued• Phosphorus 2,8,5• Sulphur 2,8,6• Chlorine 2,8,7• Argon 2,8,8• Potassium 2,8,8,1• Calcium 2,8,8,2