Conversations with the Earth Tom Burbine tburbine@framingham

1. Conversations with the EarthTom Burbinetburbine@framingham.edu

2. Chemistry • The science of matter and the changes it undergoes.

3. Atoms • Atoms are made up of 3 types of particles • Protons – positive charge (+1) • Electrons – negative charge (-1) • Neutrons – neutral charge (no charge) • Protons and Neutrons are found in the nucleus

5. Elements • Different elements have different numbers of protons • The properties of an atom are a function of the electrical charge of its nucleus

7. Definitions • Atomic Number – Number of protons • Atomic Mass – Number of protons and neutrons • U235 – atomic mass 92- atomic number • Isotopes – Same number of protons but different numbers of neutrons

9. http://www.youtube.com/watch?v=GFIvXVMbII0

10. http://www.chemicalelements.com/

11. http://www.periodicvideos.com/

12. Periodic Table • A chart in which all known elements are listed in order of atomic number • http://theodoregray.com/periodictable/

13. http://cosmiclog.msnbc.msn.com/_news/2011/01/26/5925968-see-the-worlds-smallest-periodic-tablehttp://cosmiclog.msnbc.msn.com/_news/2011/01/26/5925968-see-the-worlds-smallest-periodic-table

14. Period – Horizontal row • Across any period, the properties of elements change • Group – Vertical column • Down any group, the properties of elements are very similar

16. Radioactivity • Radioactivity – decay of an atomic nucleus • All elements with an atomic number greater than 82 (lead) are radioactive

17. Bohr’s Planetary Model • Electrons orbit the nucleus in specific energy levels • Level n=1 is closest to nucleus • Level n=2 is second closest

19. Shell Model • Electrons behave as they are arranged in a series of concentric shells around the nucleus • Innermost shell can contain 2 electrons • The second and third shells can contain 8 electrons each • The fourth and fifth shells can contain 18 electrons each

20. Valence electrons are the electrons in the outermost shell • These electrons participate in chemical bonding

23. Ion • Ion – an electrically charged particle created when an atom either loses or gains one or more electrons

27. Ionic Bond • Ionic bond – chemical bond in which an attractive electric force holds an opposite charge together

28. Covalent Bond • Covalent bond – a chemical bond in which atoms are held by their mutual attraction for two or more electrons share • Molecules are held together by covalent chemical bonds

31. Metallic Bonds • Atoms "share" electrons that float about in a general electron cloud

33. Charges need to balance • Na ions carry a +1 charge • Cl ions carry a -1 charge • Na+ + Cl- → NaCl (Sodium chloride)

34. HCl – Hydrogen Chloride • Li2O – Lithium Oxide • CO – Carbon Monoxide • CO2 – Carbon Dioxide

36. http://www.hulu.com/watch/63320/cosmos-the-lives-of-the-stars#s-p1-so-i0http://www.hulu.com/watch/63320/cosmos-the-lives-of-the-stars#s-p1-so-i0

37. Any Questions?