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

Objectives - 1-4 Identify the names and symbols of common elements. Describe characteristics and location of atomic particles. (Composition and charge) Describe the electron cloud model of the atom. Explain how electrons are arranged in an atom.

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

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

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)

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

Protons and Neutrons are found in the nucleus of an atom

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

http://faculty.washington.edu/smcohen/320/Democritus.jpg Atomic Model 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://academic.shu.edu/honors/aristotle.jpg

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

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

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

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

In-Class Assignment/Homework 19.1 Reinforcement WKT

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