Creating a Positive Learning Environment for Everyone Be respectful of your classmates Save conversation for clicker portions of lecture Put cell phones in “airplane” mode Turn off tablets Close laptops

Announcements Weak Acid Unknown Lab write-up due tomorrow in discussion. Electronic HW #6 Type 1 due Monday, Nov. 27th at 7:00pm Electronic HW #6 Type 2 due Wednesday, Nov. 29th at 7:00pm

Clicker #1 Which of the following is an endothermic process? A) A solid becoming a liquid B) Water vapor condensing C) A match burning D) Liquid water freezing E) All are endothermic processes

Clicker #2 How many of the following statements about atomic theory are still believed to be true? I. All atoms of the same element are identical. II. Negatively charged particles are embedded in a positively charged cloud throughout the atom. III. As verified by Rutherford, only positively charged particles called protons are found inside the nucleus. IV. J.J. Thomson provided the first experimental support for the atom. A) 0 B) 1 C) 2 D) 3 E) 4

Various Atomic Models Dalton: Law of Definite Proportions. (He concludes that atoms are indivisible and have mass.) J.J. Thompson: atoms emit tiny negative particles. (Therefore atoms not indivisible!) William Thompson: formulates the Plum Pudding Model. (Electrons moving in a positively charged cloud.) Rutherford: Some α-particles bounce back when shot at atoms. (There is a concentration of mass with a positive charge in the atom – the nucleus.)

Electromagnetic Radiation: Visible Spectrum

(resistance through a wire) Example: Light Bulb Energy as Light and Heat Heating Wire (resistance through a wire)

Clicker #3 Why does the pickle (the system) give off light? Choose the best answer. A) If you run electricity through anything, it will give off light. B) When protons are in an excited state due to electricity, they glow. C) The pickle contains sodium. The electricity is causing the neutrons inside sodium to move across between the two forks and thus make it glow. D) Energy was put into the pickle (by electricity) so it’s returning back to a lower energy state by releasing light.

Niels Bohr Model http://abyss.uoregon.edu/~js/cosmo/lectures/lec08.html

Clicker #4 When an electron is excited in an atom or ion A) the electron moves further from the nucleus. B) only specific quantities of energy are released in order for the electron to return to its ground state. C) white light is never observed when the electron returns to its ground state. D) the electron is only excited to certain energy levels. E) All of the above statements are true when an electron is excited.