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Introduction to the Periodic Table Representative Elements Transition Elements.

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Presentation on theme: "Introduction to the Periodic Table Representative Elements Transition Elements."— Presentation transcript:

1 Introduction to the Periodic Table Representative Elements Transition Elements

2  In 1830 there were 55 elements isolated and named  Dmitri Mendeleev’s (1869) developed a Table of Elements by ordering them in increasing atomic mass ◦ Elements with similar properties fell into groups  Mendeleev left 3 spaces for elements yet to be discovered and spurred interest in finding those elements (he also predicted their properties ◦ (15 years later all were identified)

3  Henry Moseley improved periodic table by placing them in increasing atomic number  This made it possible to see exactly how many elements yet to be discovered

4  Ordered by increasing atomic number (protons)  Organized in rows call periods (1-7 rows) ◦ Properties change gradually from 1 row to next  Columns on the periodic table are called groups or families (18 groups) ◦ Groups contain elements with similar physical and chemical properties ◦ Representative elements (8 groups) are from groups 1,2,13-18)  Include elements that are metals, nonmetals, metalloids

5  Transition elements: elements from group 3-12 ◦ All are metals  Inner transition elements are below main table and include lanthanide and actinide series ◦ (named by series that follows lanthanum and actinium (most are radioactive)



8  Are solid (with exception of Mercury Hg)  Have high melting point  Has metallic luster, good conductor of heat and electricity  Is malleable (can hammer it)  Is ductile (can be stretched)

9  Nonmetals are usually ◦ Gases or brittle solids at room temperature ◦ Poor conductors of heat and electricity ◦ 17 nonmetals, some are essential for life (O, C,S, N, P, and I)  Metalloids are usually: ◦ In between metals and nonmetals that share properties of metals and nonmetals

10  Shows name of element, symbol, atomic number, atomic mass and the state of matter (gas, liquid or solid)

11  One or two letter symbols where the first letter is capitilized, second letter is small letter ie Ca, Pb, Na, Si  Some names come from first letter of element, others greek or latin names, some for countries discovered

12  Groups 1 and 2 ◦ Both groups are active metals (except H) because they easily combine with others substances ◦ H shares properties with these groups

13  Group 1 ◦ Silvery solids with low density and low melting points ◦ As move down the column they become more reactive ◦ Include Li,Na,K,Rb,Cs, Fr

14  Group 2 ◦ Denser, harder and higher melting point than group1 (alkali) ◦ Are reactive, but not as much as alkali metals

15  Group 13 Boron Family  all are metals except B which is a metalloid ◦ Cookware is made from B, Al for cans,Ga used in computer chips  Group 14 Carbon Family ◦ C is nonmetalic, Si and Ge are metalloids, Tn and Pb are metals  Semi conductors in computers are made from Si because they conduct some electrical current but is buffered to help maintain certain levels of conductivity

16  Group 15: Nitrogen groups  N,P,As,Sb,Bi (nonmetal,metalloid, and metals)  Nitrogen composed of 78% of atmosphere yet it can’t be utilized by organisms until it is change to nitrates  Nitrogen fixing bacteria on roots of organisms can fix nitrogen into nitrates

17  Group 16 Oxygen Family  O and S are essential for life  Te and Po are both metalloids  20% earths atmosphere is made of O ◦ Needed for respiration for energy production of animals ◦ O is needed for combustion, ozone layer protects us from ultraviolet radiation  S is solid, yellow nonmetal, used in sulfuric acid, production of fertilizers, rubber etc Se is important as trace minerals, conducts electricity

18  Group 17 Halogen family  All are nonmetals except At radioactive metalloid  Halogen means salt-former like NaCl  All halogens make salt  As move down the group they become less active

19  Group18 The Noble Gases  All are gases, do not react with other elements  Uses include the Neon lights in advertisments ◦ Electricity passes through tubes containing noble gases that when mixed with noble gases produces different colored lights  Bottom of group is radioactive Ra

20  Metals in the Middle: groups 3-12  Iron Triad (similar properties)  Iron Fe, cobalt Co, and nickel Ni  Fe used with other metals and C to form alloys like steel  Uses of Transition Elements ◦ Higher melting points, used in filaments of lightbulbs: tungsten W has highest melting point (3410 ℃ ) ◦ Mercury Hg, lowest melting point -39 ℃ ◦ Platinium group Ru,Rh, Pa, Os, Ir, Pl similar properties  Catalysts are substanes that can make something happen faster but doesn’t change themselves (platinium group )

21  Lanthanides series: rare earths because not found commonly on earth ◦ Soft metals, hard to tell apart in same ores, Ce makes up 50%of an alloy called misch used in flints lighters  Actinides series: all are radioactive Th, Pa and U are only ones found in nature ◦ Rest are synthetic elements (man made)

22  Dentistry and Dental Material ◦ Amalgam (mixture of silver, copper, tin, and mercury) is the silver filling ◦ Nickel and titanium alloys are used in wires on braces

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