The Periodic Table

1. The Periodic Table Introduction to the Periodic Table Representative Elements Transition Elements

2. Development of the Periodic Table • 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. Moseley’s Contribution • 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. Today’s Periodic Table • 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. Today’s Periodic Table • 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. Metals • 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 and metalloids • 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. Element Key • Shows name of element, symbol, atomic number, atomic mass and the state of matter (gas, liquid or solid)

11. Symbols for the Element • One or two letter symbols where the first letter is capitilized, second letter is small letter ieCa, Pb, Na, Si • Some names come from first letter of element, others greek or latin names, some for countries discovered

12. Representative elements • 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. Alkali metals • 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. Alkaline Earth Metals • Group 2 • Denser, harder and higher melting point than group1 (alkali) • Are reactive, but not as much as alkali metals

15. Groups 13-18 • 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. Groups 13-18 • 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. Groups 13-18 • 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. Groups 13-18 • 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. Groups 13-18 • 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. Transition Elements • 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. Inner Transition Element • 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. Inner Transition Element • 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