Chapter 19 – Properties of Atoms and the Periodic table

1. Chapter 19 – Properties of Atoms and the Periodic table 19.1 – Structure of the Atom Guided Notes Page

2. Objectives Identify the names and symbols of common elements. Describe the electron cloud model of the atom. Explain how electrons are arranged in an atom.

3. Scientific Shorthand • Chemical symbols = used to abbreviate the name of an element • Accepted and used worldwide http://www.ptable.com/

4. One capital letter or one capital letter and 1-2 lowercase letters • Some are simply the 1st (or 1st and another letter) of the element’s name • H = Hydrogen Ca = Calcium • Others are derived from the Latin name of the element • Ag = Silver Fe = Iron

5. Latin names Cu – Cuprum (Copper) Au – Aurum (Gold) Fe – Ferrum (Iron) Pb – Plumbum (Lead) Hg – Hydrargyum (Mercury) K – Kalium (Potassium) Ag – Argentum (Silver) Na – Nathum (Sodium) W – Wolfram (Tungsten)

6. Atomic Components • Atom = smallest piece of matter that retains properties of the element • Atomic Particles • Protons (p+) = positive charged particles • Neutrons (no) = uncharged particles • Electrons (e-)= negative charged particles

7. Protons and Neutrons are found in the nucleus of an atom

8. Quarks • Scientists confirm that p+ & no are made of smaller particles called Quarks • 6 uniquely different quarks • Arrangement of 3 = proton • Different arrangement of 3 = neutron

9. 400 B.C. – Democritus proposed the idea that atoms make up all substances Aristotle disputed Democritus' theory and said matter was uniform throughout and not composed of smaller particles Aristotle had more clout and his theory held for more than 2000 years http://faculty.washington.edu/smcohen/320/Democritus.jpg Atomic Model http://academic.shu.edu/honors/aristotle.jpg

10. Atomic Model • 1800s – John Dalton was able to prove atoms exist • Solid sphere = atom • Provided physical explanation for chemical reactions

11. http://wind.cc.whecn.edu/~mechalke/chapter5/Thomson.gif Atomic Model • 1904 – J.J. Thomson said electrons were found throughout positive sphere • 1911 – Ernest Rutherford said atoms was not a sphere but rather a central mass (nucleus) surrounded by electrons http://www.cfo.doe.gov/me70/manhattan/images/AtomLabeled.gif

12. Atomic Model • 1913 – Niels Bohr said electrons move in fixed orbits http://www.green-planet-solar-energy.com/images/bohr_atom.gif

13. Atomic Model - current • Electron Cloud Model = area around nucleus where electron likely to be found • Electrons move so quickly it is difficult to pinpoint exact location • Electrons do not follow a rigid pattern of movement

14. In-Class Assignment/Homework • 19.1 Reinforcement WKT

15. Modeling an Aluminum Atom • Gather 13 blue dots, 13 green dots and 14 red dots • Arrange all blue dots and all red dots on a flat surface to represent the nucleus of an atom • Each blue dot = proton • Each red dot = neutron • Position 2 green dots 2 cm from the nucleus • Position 8 green dots 5 cm from the nucleus • Position 3 green dots 8 cm from the nucleus • Answer questions from pg. 581 on back of paper