John Singer, Jackson Community College Chemistry for Changing Times, Thirteenth Edition Lecture Outlines © 2013 Pearson Education, Inc. Chapter 3 Atomic Structure

Electricity and the Atom Electrolyte: A compound that conducts electricity when molten or dissolved in water. Electrodes: Carbon rods or metallic strips that carry electrical current. © 2013 Pearson Education, Inc. 2 Chapter 3

Anode: A positive electrode. Cathode: A negative electrode. © 2013 Pearson Education, Inc. 3 Chapter 3 Electrolysis

Ions Ion: An atom or group of atoms with a charge. Anion: A negative ion. Cation: A positive ion. © 2013 Pearson Education, Inc. 4 Chapter 3

Cathode Ray Tubes Mid-1800s: Crookes’s tube © 2013 Pearson Education, Inc. 5 Chapter 3

Thomson Experiment 1897, Joseph John Thomson: Determined the charge: Mass ratio of cathode rays (discovered electrons). © 2013 Pearson Education, Inc. 6 Chapter 3

Goldstein’s Experiment: Positive Particles 1886, Goldstein: Observed positive rays using a perforated cathode. © 2013 Pearson Education, Inc. 7 Chapter 3

Electron Charge 1909, Robert Millikan: Using the oil-drop experiment, Millikan determined the charge of an electron. © 2013 Pearson Education, Inc. 8 Chapter 3

X-Rays 1895, Wilhem Roentgen: Using a cathode ray tube, Roentgen discovered X-rays. © 2013 Pearson Education, Inc. 9 Chapter 3

Radioactivity 1895, Antoine Becquerel: Discovered radioactivity. During the following decade and a half, Marie and Pierre Curie worked to isolate pure radioactive substances. © 2013 Pearson Education, Inc. 10 Chapter 3

Three Types of Radioactivity © 2013 Pearson Education, Inc. 11 Chapter 3

© 2013 Pearson Education, Inc. 12 Chapter 3 Three Types of Radioactivity

Rutherford Gold Foil Experiment In 1911, Ernest Rutherford published a paper in which he detailed his Gold Foil Experiment.Using an apparatus similar to that shown below, Rutherford discovered the atomic nucleus. © 2013 Pearson Education, Inc. 13 Chapter 3

© 2013 Pearson Education, Inc. 14 Chapter 3 Rutherford Gold Foil Experiment

Subatomic Particles © 2013 Pearson Education, Inc. 15 Chapter 3

Atomic Structure Atomic number: The number of protons in a nucleus. Mass number: The sum of protons and neutrons in a nucleus. © 2013 Pearson Education, Inc. 16 Chapter 3

Isotopes Isotopes have the same atomic number, but have different mass numbers (same number of protons, but different number of neutrons). © 2013 Pearson Education, Inc. 17 Chapter 3

Nuclear Symbol x = Element symbol A = Mass number Z = Atomic number © 2013 Pearson Education, Inc. 18 Chapter 3 A Z x

Flame tests: Different elements give different colors to a flame. © 2013 Pearson Education, Inc. 19 Electron Arrangement: The Bohr Model Chapter 3

Continuous spectra: When light emitted from a solid substance is passed through a prism, it produces a continuous spectrum of colors. © 2013 Pearson Education, Inc. 20 Chapter 3 Electron Arrangement: The Bohr Model

Line spectra: When light from a gaseous substance is passed through a prism, it produces a line spectrum. © 2013 Pearson Education, Inc. 21 Chapter 3 Electron Arrangement: The Bohr Model

Quantum: A tiny unit of energy produced or absorbed when an electron makes a transition from one energy level to another. © 2013 Pearson Education, Inc. 22 Chapter 3 Electron Arrangement: The Bohr Model

When electrons are in the lowest energy state,they are said to be in the ground state. When energy from a flame or other source is absorbed by the electrons, they are promoted to a higher energy state (excited state). When an electron in an excited state returns to a lower energy state, it emits a photon of energy, which may be observed as light. © 2013 Pearson Education, Inc. 23 Chapter 3 Electron Arrangement: The Bohr Model

Electron Arrangement Energy states or levels are sometimes called shells. © 2013 Pearson Education, Inc. 24 Chapter 3

The Quantum model of the atom is a probability-based model. It is composed of principal energy levels, sublevels, and orbitals. © 2013 Pearson Education, Inc. 25 Chapter 3 Electron Arrangement: The Quantum Model

Principal energy levels (shells): Roughly correlate to the distance that an electron is from an atom’s nucleus. Sublevels (subshells): Each principal energy level (n) is divided into n sublevels. Orbitals: Orbitals are regions in space that represent a high probability of locating an electron. Each sublevel has one or more orbitals. © 2013 Pearson Education, Inc. 26 Chapter 3 Electron Arrangement: The Quantum Model

© 2013 Pearson Education, Inc. 27 Chapter 3 Electron Arrangement: The Quantum Model

© 2013 Pearson Education, Inc. 28 Chapter 3 Electron Arrangement: The Quantum Model

Electron configurations: Allow us to represent the arrangement of the electrons in an atom. © 2013 Pearson Education, Inc. 29 Chapter 3 Electron Arrangement: The Quantum Model

© 2013 Pearson Education, Inc. 30 Chapter 3 Electron Arrangement: The Quantum Model

The order-of-filling chart: © 2013 Pearson Education, Inc. 31 Chapter 3 Electron Arrangement: The Quantum Model

© 2013 Pearson Education, Inc. 32 Chapter 3 Electron Arrangement: The Quantum Model

The periodic table is considered by many to be the most predictive tool in all of chemistry. It is composed of vertical columns called groups (or families) and horizontal rows called periods. © 2013 Pearson Education, Inc. 33 Chapter 3 Electron Configurations and the Periodic Table

Groups (families): Vertical columns in the periodic table. Groups contain elements with similar chemical properties. Periods: Horizontal rows in the periodic table. Elements in a period demonstrate a range of properties from metallic (on the left) to nonmetallic (on the right). © 2013 Pearson Education, Inc. 34 Chapter 3 Electron Configurations and the Periodic Table

Valence electrons: Valence electrons are the electrons in the outermost principal energy level of an atom. These are the electrons that are gained, lost, or shared in a chemical reaction. Elements in a group or family have the same number of valence electrons. © 2013 Pearson Education, Inc. 35 Chapter 3 Electron Configurations and the Periodic Table

Some groups in the periodic table have special names: Alkali Metals: Group 1A –Valence electron configuration: ns 1 Alkaline Earth Metals: Group 2A –Valence electron configuration: ns 2 Halogens: Group 7A –Valence electron configuration: ns 2 np 5 Noble Gases: Group 8A –Valence electron configuration: ns 2 np 6 © 2013 Pearson Education, Inc. 36 Chapter 3 Electron Configurations and the Periodic Table

Metals, Nonmetals, and Metalloids: © 2013 Pearson Education, Inc. 37 Chapter 3 –Metals Metallic luster, conduct heat and electricity, malleable, and ductile. Examples are sodium and copper. –Nonmetals Dull luster, nonconductors, and brittle in the solid state. Examples are sulfur and bromine. –Metalloids Demonstrate properties of both metals and nonmetals. Examples are silicon and arsenic. Electron Configurations and the Periodic Table

© 2013 Pearson Education, Inc. 38 Chapter 3 Electron Configurations and the Periodic Table