The Periodic Table (c. 19)

1. The Periodic Table (c. 19) Describes the basic structure of the atom as protons, neutrons and electrons in specific arrangements. 7.2 Relates the relative number of protons and electrons to chemical charge and reactivity. 9.1 Predicts whether two elements will chemically combine based on their position on the periodic table. 9.3 Apply rules for naming simple chemical compounds (ionic). E. Q. How does the atomic structure impact chemical change and reactivity? E. Q. What is the relationship between location and chemical reactivity?

2. Periodic Table Notes (History) After John Dalton in 1808 came up with his atomic theory which included, “Atoms of different elements are different,” physical and chemical properties of all the elements had to be discovered.

3. In 1869, Dmitri Mendeleev University of St. Petersburg, Russia 63 known elements at the time Listed the element on cards lightest  heaviest Grouped them according to physical & chemical properties. Very time consuming gathering the data. Discovers the “periodic properties” of the elements, the properties repeated over and over. Makes bold predictions  predicted the weights and properties of then unknown elements. 3-4 years later an element is discovered that proves him to be correct.

4. Henry Moseley (~1915) former student of Ernest RutherfordWhat is Rutherford known for? Worked on the Gold Foil Experiment. Using the data on the newly found proton & Niels Bohr’s data on electron cloud energy levels. Lists the elements according to Atomic Number (# of protons). Groups them according to electron energy levels and sublevels. The Law of Periodicity holds true. Dies in battle during World War I.

5. Periodic Table Notes I. General Information on the Elements Hydrogen & helium make up 99% of all the atoms in the universe. Metals are on the left side and nonmetals are on right side of the zigzag line and the metalloids are on the line. Earth’s crust is mainly oxygen and silicon found in rocks. Human body is mainly carbon, hydrogen and oxygen. Approximately 75% water (H2O). 90 natural elements, #1 hydrogen the smallest and #92 uranium the largest. WHAT IS STRANGE ABOUT THAT? Atomic numbers 43 (Technetium) and 61 (Promethium) are both smaller than Uranium but have never been found in nature, thus are man-made. Only 30 can be found in elemental form (free and uncombined, pure).

6. US Coins • Penny made before 1982, 95% copper • & 5% zinc, today, 2.5% copper & 97.5% zinc. • Nickels 75% copper and 25% nickel • all others 8.5% nickel & 91.5% copper • Coins prior to 1965 were 90% silver. • The atomic number is the number of protons in an atom. • The mass number is the number of protons and neutron, both found in the nucleus. • Valence electrons are the electron on the outer energy level and furthest away from the nucleus (have the most energy). • A period (or a series) is a horizontal row across the periodic table. • Groups (or families) are the vertical columns running down the periodic table.

7. Group 1 Alkali Metals • (Li, Na, K, Rb, Cs, Fr) • 1 valence electron. • Soft metals, can be cut with a knife. • VERY reactive. • Low melting points. • React quickly with the oxygen in the air. • Never found pure in nature. • React violently in water.

8. Exception is Hydrogen. • NOT a member of the Alkali Metals. • A gas (nonmetal). • Lightest substance known. • 93% of all atoms in the universe are hydrogen.

9. Group 2 Alkaline Earth Metals • (Be, Mg, Ca, Sr, Ba, Ra) • 2 valence electrons • Highly reactive • Beryllium has such high boiling point it is used in the heat shields on the space shuttle. • Magnesium and calcium are the most common. Ca found in cement and used in water softeners.

10. Group 13 Boron Family (B, Al, Ga, In, Tl) • 3 valence electrons. • Boron is a metalloid used to make • Borax, all others are metals. • Aluminum is the third most • abundant element on Earth, • most abundant metal. • Gallium melts in your hand.

11. Group 14 Carbon Family • (C, Si, Ge, Sn, Pb) • 4 valence electrons. • Carbon forms over 5 million compounds. • Silicon is the 2nd most abundant element in the Earth’s crust. • Silicon & Germanium are used in electronics. • Lead used in water pipes before it was discovered to be poisonous.

12. Group 15 Nitrogen Family • (N, P, As, Sb, Bi) • 5 valence electrons. • Nitrogen is the most abundant element in air, 78%. • Phosphorus used in weapons. Burns very hot!! • Bismuth has a low melting point used for “triggers” in automatic sprinkler systems.

13. Group 16 Oxygen Family (O, S, Se, Te, Po) • 6 valence electrons. • Highly reactive. • Oxygen is the most common element on Earth, 50% Earth’s crust, 20% of air and 33% of water. • Sulfur used in Vulcanization of rubber.

14. Group 17 Halogens“salt-makers” • (F, Cl, Br, I, At) • 7 valence electrons • VERY reactive, fluorine is the most reactive of all elements. • Never found pure in nature. • React with metals to form salts • example: table salt - NaCl.

15. Group 18 the Inert or Nobel Gases • (He, Ne, Ar, Kr, Xe, Rn) • 8 valence electrons “Stable 8” • . • NON REACTIVE  so ALWAYS found pure in nature. • Helium is rare on Earth, yet 2ndmost abundant element in the universe. • Most are used • in “neon” signs.

16. Groups 3-12 the Transition Metals • All are similar (metal properties). • The number of valence electrons varies. • Many elements have multiple # of valence electrons.

17. Lanthanide Series “rare Earth elements” • Actinide Series • All radioactive • Uranium is the largest, heaviest nature element. • Most are man-made or synthetic elements.

18. METALS vs NONMETALSand the METALLOIDS

19. METALS • Found on the left side of the periodic table. • Shiny or lustrous. • Conductors of electricity & heat. • Malleable, ductile & elastic. • Usually high melting & boiling points. • Lose electrons when bonding & form positive ions.

20. NONMETALS • Found on the right side of the periodic table. • Insulators  poor conductors. • Brittle, shatter, break under pressure. • Gain electrons when bonding to form negative ions. • Dull luster. • Can form covalent bonds  electrons are shared to form the bonds.

21. METALLOIDS • Found over & under the zigzag line. • Have properties of both metals & nonmetals. • Silicon & germanium  dull, brittle shatter and conductor. • Aluminum is considered a metal.

22. Valence electrons are important because that is where bonding occurs. • When elements bond with each other they do one of three things with their valence electrons in order to get to the “STABLE 8”: • Gain electrons & become negative ions = ionic bonding • Lose electrons & become positive ions = ionic bonding • Shareelectrons & become a molecule • = covalent bonding