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Elements and their Properties.  Metals (on the left of the stair-step line)  Usually have common properties  Good conductors of heat and electricity.

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Presentation on theme: "Elements and their Properties.  Metals (on the left of the stair-step line)  Usually have common properties  Good conductors of heat and electricity."— Presentation transcript:

1 Elements and their Properties

2  Metals (on the left of the stair-step line)  Usually have common properties  Good conductors of heat and electricity  Have luster = reflect light  Are malleable = can be hammered or rolled into sheets  Are ductile = drawn into wires  All, but one, are solid at room temperature

3  Ion = charged particle that has either more or fewer electrons than protons  The atoms of metals typically have one to three electrons in their outer energy levels.  Metals tend to give up their electrons because of the strength of charge of the protons in the nucleus.  When metals combine with nonmetals, the atoms of the metals tend to lose electrons to the atoms of the nonmetals – thus forming ionic bonds.

4  Metallic bonding = when positively charged metallic ions are surrounded by a cloud of electrons  Because of this, the electrons move freely among the many positively charged ions.  This type of bonding explains many properties of metals:  Malleability/ductility – metals do not break instead the ions slide past each other  Good conductor of electricity – outer-level electrons are weakly held

5  Alkali metals (Group 1)  Shiny, malleable, and ductile  Good conductors of heat and electricity  Are softer than most metals  Are the most reactive  They react rapidly, sometime violently, with oxygen and water  Since they combine readily with other elements, they don’t occur in nature in their elemental form  Are stored in substances that are unreactive, such as oil  Have one electron in its outer energy level that is given up, resulting in a +1 ion

6  Alkaline Earth metals (Group 2)  Shiny, malleable, and ductile  Combine readily with other elements, so they are not found as free elements in nature  Has two electrons in its outer energy level that are given up, resulting in a +2 ion

7  Transition elements (Group 3-12)  Are called transition elements because they are the elements in transition between groups 1 and 2 and groups 13 through 18  Are the most familiar since they occur in nature as uncombined elements  Often form colored compounds

8  Iron triad (found in Groups 8, 9, and 10)  Iron, cobalt, and nickel  Used in the process to make steel  Coinage metals (found in Group 11)  Copper, silver, and gold  Were used in coins, but are not anymore since they are so expensive  Copper is often used in electrical wiring because of its superior ability to conduct electricity  Used in jewelry because of their attractive color, relative softness, resistance to corrosion, and rarity

9  Zinc, cadmium, and mercury  Found in Group 12  Zinc and cadmium are used to coat, or plate, other metals  Cadmium is used in rechargeable batteries  Mercury, being a liquid, is used in thermometers, thermostats, switches, and batteries  It is poisonous and can accumulate in the body.  People have died after eating fish that lived in mercury- contaminated water.

10  Inner Transition metals  They fit in the periodic table between Groups 3 and 4 in periods 6 and 7.  To save room, they are listed below the table.  Known as the Lanthanides and Actinides  Read “Metals in the Crust” on page 577 on your own.

11  Nonmetals  Usually are gases at room temperature  Not malleable or ductile  Most do not conduct heat or electricity well  Generally they are not shiny (lack luster)  All nonmetals except for hydrogen are right of the stair-step line

12  Most nonmetals can form ionic and covalent compounds.  When nonmetals gain electrons from metals, the nonmetals become negative ions in ionic compounds.  When bonded with other nonmetals, atoms of nonmetals usually share electrons to form covalent compounds.

13  Hydrogen  About 90% of all the atoms in the universe are hydrogen.  Most is found in the form of water.  It is derived from the Greek word for “water forming.”  It is highly reactive.  Diatomic molecule = consists of two atoms of the same element in a covalent bond.  H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2

14  The Halogens (Group 17)  Are very reactive in their elemental form.  Fluorine is the most chemically active of all elements.  Can be identified by their distinctive colors.  Cl = greenish-yellow; Br = brownish-orange; and I = violet  Have seven electrons in their outer energy level, so only one electron is needed to complete the energy level.  If it gets the electron from a metal, an ionic compound, or salt, is formed.  In the gas state, halogens form reactive diatomic covalent molecules.

15  Halogens have many uses:  Fluorides are added to toothpaste and to city water systems to prevent tooth decay.  Chlorine compounds are added to water to disinfect it.  Bleach also contains chlorine.  Bromine, the only liquid nonmetal, is used in dyes in cosmetics.  Iodine undergoes sublimation, or the process of a solid changing directly to a vapor without forming a liquid.  It is essential in your diet to produce a hormone and to prevent a goiter.

16  The Noble Gases  Exist as isolated atoms  Are stable because their outermost energy levels are full  No naturally occurring noble gas compounds are known, but several have been created in a lab.  The stability of noble gases makes them useful.  Helium is used in blimps and balloons.  Neon and argon are used in “neon lights.”  Argon and krypton are used in electric light bulbs to produce light in lasers.

17  Metalloids  Can form ionic and covalent bonds with other elements  Can have metallic and nonmetallic properties  Semi-conductors = the name given to some metalloids that can conduct electricity better than most nonmetals, but not as well as some metals.  With the exception of aluminum, the metalloids are located along the stair-step line.

18  The Mixed Groups 13, 14, 15, 16, and 17 – contain metals, nonmetals, and metalloids.  The Boron Group = Group 13  The Carbon Group = Group 14  The Nitrogen Group = Group 15  The Oxygen Group = Group 16  The Halogens = Group 17

19  Allotropes = different forms of the same element having different molecular structures.  Silicon  One is a hard, gray substance.  The other is a brown powder.  Carbon  Diamond – clear and extremely hard  Graphite – black powder  Buckminsterfullerene – soccer-ball shaped molecule used to synthesize extremely thin, graphitelike tubes.

20  Transuranium elements  Elements that have more than 92 protons.  These elements do not belong exclusively to the metal, nonmetal, or metalloid group.  All are synthetic and unstable, and many disintegrate quickly.

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