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

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.

Scientific Shorthand  Chemical symbols = used to abbreviate the name of an element  Accepted and used worldwide

 One capital letter or one capital letter and 1-2 lowercase letters  Some are simply the 1 st (or 1 st and another letter) of the element’s name  H = HydrogenCa = Calcium  Others are derived from the Latin name of the element  Ag = SilverFe = 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 (n o ) = uncharged particles  Electrons (e - )= negative charged particles

 Protons and Neutrons are found in the nucleus of an atom

Quarks  Scientists confirm that p+ & n o are made of smaller particles called Quarks  6 uniquely different quarks  Arrangement of 3 = proton  Different arrangement of 3 = neutron

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

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

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

Atomic Model  1913 – Niels Bohr said electrons move in fixed orbits

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