Transition elements
Metals in the Middle
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Groups 3 – 12 = transition elements
All metals
Change less noticeably across period than representative elements
Iron triad (p448)
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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)
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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
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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
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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)
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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
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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