Transition elements Metals in the Middle Groups 3 – 12 = transition elements All metals Change less noticeably across period than representative elements Iron triad (p448) Period 4 – iron, cobalt, nickel Such similar properties = iron triad Are magnetic Industrial magnets = alloy of nickel, cobalt, aluminum Nickel = used in batteries Iron o necessary part of hemoglobin o mixed with other metals and carbon to create steel = used in buildings as structures (give strength) Uses of Transition Elements (p449) Have higher melting points than representative elements Tungsten = used in lightbulbs b/c has highest melting point of any element and doesn’t melt when electric passed thru it. Mercury = o lowest melting point = used in thermometers/barometers o only metal that is a liquid at room temp. o poisonous to humans chromium o name from greek word for color, used in paints o many transition elements combine with other substances to form brilliant colors ruthenium, rhodium, palladium, osmium, iridium, platinum = o platinum group b/c similar properties do not combine easily with other elements = can be used as catalysts o nickel, zinc, cobalt can also be used as catalysts catalysts are used to produce electronic and consumer goods, plastics, medicines Inner Transition Elements (p450) Lanthanides rare earth (b/c at one time thought to be rare) actually found combined with Oxygen in earth’s crust soft metals – can be cut with knife hard to separate b/c so similar and occur in same ore not rare – cerium occurs more often than lead in earth’s crust Cerium – used in misch metal to make flint (also includes lanthanum, neodymium and iron) Actinides bottom period all are radioactive – unstable, decay to form other elements Thorium, protactinium, uranium – only actinides found naturally on earth All other actinides are synthetic Plutonium = fuel in nuclear power plants Americium – used in smoke detectors Californium - used to kill cancer Dentistry and Dental Material (p452) Amalgam = used to fill cavities for 150 years Amalgam = mixture of silver, copper, tin, mercury Ppl are concerned about mercury vapor so now dentist use resins Orthodontists – use nickel and titanium alloys for brace wires o Wires heated to lock in shapes o If they try to get out of shape, the will try to return to original shape P451 – Visualizing Synthetic Elements - Particle accelerator – used to make synthetic elements with atomic number greater than uranium Atomic nuclei are collided at high speeds to fuse nuclei together = new heavier isotopes May survive for only a moment until breaking apart