Presentation on theme: "Introducing the Elements The Element Song. 1869: Dmitri Mendeleev Russian chemist Arranged elements in tabular form so that elements with similar properties."— Presentation transcript:
1869: Dmitri Mendeleev Russian chemist Arranged elements in tabular form so that elements with similar properties were in the same column When listed in order by mass, elements generally repeat properties in groups of 8 (Law of Octaves)
The First Periodic Table Most tables at the time listed elements by mass Mendeleev also arranged elements by mass, but left several “holes” in his table and occasionally reversed the order of elements to fit the properties of others in that column The “holes” were later filled in with newly discovered elements that had the properties predicted by Mendeleev’s table. The reason for the reversal of elements was explained later by Henry Moseley, who noted that the elements were in order by atomic number (number of protons) rather than by mass
Know the following Elements 1-20, 24-30, 33, 35-38, 47, 48, 50, 53-56, 78, 79, 80, 82, 86, 92 1-20, 24-30, 33, 35-38, 47, 48, 50, 53-56, 78, 79, 80, 82, 86, 92 Names and symbols Names and symbols
1.Sodium 2.Mercury 3.Zinc 4.Bromine 5.Calcium 6.Fluorine 7.Helium 8.Manganese 9.Nickel 10.Uranium 11. C 12. O 13. Pb 14. Sn 15. Cr 16. Mg 17. Ba 18. K 19. Si 20. Ag
1.boron 2.berylluim 3.iron 4.chlorine 5.lithium 6.magnesium 7.argon 8.cobalt 9.potassium 10.phosphorous 11. Al 12. Cd 13. As 14. Pt 15. Cu 16. Sr 17. Ba 18. Ne 19. Rn 20. Kr
Hydrogen Most abundant element in the universe Why? Makes up most the mass of stars Can be H+ (hydrogen ion) or H- (hydride ion) Used in Fuel Cells: How Stuff WorksHow Stuff Works In Fusion, H is converted to He
Alkali Metals: Li, Na, K, Rb, Cs, Fr Most reactive of the metals, +1 ions Stored under kerosene or mineral oil Na and K most important Na 2 CO 3 and NaHCO 3 two important compounds K is an important plant nutrient (macronutrient) Fertilizers: N-P-K (Not found in nature in elemental form)
Alkaline Earth Metals: Be, Mg, Ca, Sr, Ba, Ra Harder, more dense, and less reactive than alkali metals Ca, Sr, and Ba most alike Hard Water: Ca2+ and Mg2+ ions Epsom salt: MgSO 4 Boiler Scale
…..more on the alkaline earths CaCO 3 is limestone becomes marble Limestone is most abundant rock in the earth’s crust CaO “Lime” or “quicklime” CaSO 4 “Plaster of Paris” (building material) Plaster of Paris footprints
Do You Know? Most abundant element in the universe? Most abundant rock in the earth’s crust? Formula for the “plaster of Paris”? Ions found in “hard” water? Three numbers of fertilizer? How do alkaline earth metals compare to the alkali metals in (a) reactivity and (b) density?
Aluminum Group: B, Al, Ga, In, Tl Aluminum by far the most important Third most abundant element in the earth’s crust Important metal: abundant, light weight, strong Al 2 O 3 coating prevents corrosion
Carbon Group: C, Si, Ge, Sn, Pb Very diverse group of elements C is the basis for organic compounds CO 2 and CO 3 -2 inorganic carbon CO 2 one of the earliest gases in the atmosphere Carbon cycling one of the most important Two basic parts: (1) photosynthesis (2) respiration
Disrupting the carbon cycle CO 2 is a greenhouse gas (GWP=1) Increasing concentration by: 1.Burning fossil fuels 2.Removing vegetation Preindustrial 1800: 280 ppm 1959: 316 ppm 2010: 388 ppm 2011: 391 ppm
Silicon - Si Second most abundant element in the Earth’s crust Found in clay, sand, sandstone, silica rock, quartz, other minerals Many different bonding combinations Is a semiconductor (Silicon Valley)
Tin (Sn) and Lead (Pb) Many Industrial Uses Pb is a “heavy metal” and is toxic to many organs in the human body Impedes the development of the nervous system Taken out of gasoline in the late 1970’s and removed from most paints
The Halogens F, Cl, Br, I, At Group 17 – halogen means (salt former) The most reactive nonmetals F and Cl are gasses Br is a liquid I is a solid
Total Molar Composition of Seawater (Salinity = 35)   Compone nt Concentration (mol/kg) H2OH2O53.6 Cl − 0.546 Na + 0.469 Mg 2+ 0.0528 SO 2− 4 0.0282 Ca 2+ 0.0103 K+K+ 0.0102 CTCT 0.00206 Br − 0.000844 BTBT 0.000416 Sr 2+ 0.000091 F−F− 0.000068
Bonding: Influences Valence Electrons Nuclear Charge Atomic Size/Radius Distance between attractions Screening or Shielding Effect
Radius trends Group trend? Radius increases down a group Why? Adding new energy levels Period trend? Radius decreases across a period Why? Increasing nuclear charge has the effect of pulling electron cloud closer.
Ions and their formation Cations Formed by the loss of electrons Positively charged Usually formed from metals Are always smaller than the atom they are formed from Anions Formed by the gain of electrons Negatively charged Usually formed from nonmetallic elements Are always larger than the atom they are formed from
Ionization Energy The energy required to remove an electron from an isolated, neutral, gaseous atom. First ionization energy – energy required to remove a first electron from an atom. Second ionization energy – energy required to remove a second electron from an atom. Third ionization energy - ???? Etc....
First Ionization energies Group trend – IE 1 decreases down a group. Why? Valence electrons are further from the nucleus and the shielding effect is greater down a group. Shielding effect – occurs when core electrons “shield” or interfere with the attraction that the nucleus has for the valence electrons.
... IE cont.... Period trend – IE 1 is larger as you move across a period, left to right. Why? Atoms are smaller so valence electrons are closer to the nucleus and........ the nuclear charge is greater with no change in shielding effect (electrons are going in the same energy level)
Ionization Energy Increasing Trend Periodic Table
Successive Ionization Energies Where do the largest jumps occur for each Element and why do you think this happens?
Electronegativity A measure of the ability of an atom to attract electrons to itself when bonded to other atoms.
1.Place these elements in order of increasing: Ge, P, N, and Si (a) atomic radius (b) first ionization energy (c) electronegativity 2. Write the core configuration for the following elements: S, Ca, Sn 3.How many valence electrons does each element in #2 have?