Quantum - Quantum Theory of the Atom Chapter 7 Introduction...

Info icon This preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Quantum Theory of the Atom Chapter 7
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/01/11 18:06 Dept/Chem, METU 2 Introduction Elements that exhibit similar chemical properties were placed together in the same column of the periodic table. When metal compounds heated in flame, they emit bright colors. Li(IA) and Sr(IIA): red, Ba(IIA): green The red lights of Li and Sr can be resolved by prism into lines of different colors which distinguishes two elements. How does each atom emit particular color of light? Does the line spectrum tell us the structure ot the atom? We need to understand the arrangement of electrons in an atom (called electronic structure of an atom)
Image of page 2
11/01/11 18:06 Dept/Chem, METU 3 Topics of Discussion The Wave Nature of Light Quantum Effects and Photons The Bohr Theory of Hydrogen Atom Quantum Mechanics Quantum Numbers and Atomic Orbitals
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/01/11 18:06 Dept/Chem, METU 4 Properties of wave Wavelength, λ , is the distance between any two adjacent point of a wave The frequency, ν , of a wave is the number of wavelengths that pass a fixed point in a unit time, usually second. Unit is Hz (1/s). ν =4 Hz ν =8 Hz λ , wavelength Amplitude time distance
Image of page 4
11/01/11 18:06 Dept/Chem, METU 5 Wave property of light Light is electromagnetic wave. Electric and magnetic fields oscillate synchronously in planes perpendicular to each other. Speed of light in vacuum, c=3x10 8 m/s c= νλ E B
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/01/11 18:06 Dept/Chem, METU 6 Diffraction of light; wave property Light is diffracted when the refractive index, n, of medium changes. c = νλ (in vacuum) v = c/n (in medium) n air =1 n water =1.5
Image of page 6
11/01/11 18:06 Dept/Chem, METU 7 Electromagnetic Spectrum 1 14 9 8 10 58 . 6 10 1 456 / 10 3 - = s x nm m nm s m x Electromagnetic spectrum covers the range of frequencies and wavelengths of electromagnetic radiation.
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/01/11 18:06 Dept/Chem, METU 8 Characteristic frequency of Cs atom What is the frequency of one of the spectral lines of Cs with a wave length of 456 nm? 1 14 9 8 10 58 . 6 10 456 10 3 - - = = = s x m x s m x c λ ν
Image of page 8
11/01/11 18:06 Dept/Chem, METU 9 Continuous Spectrum Continuous Spectrum contains light of all colors(wavelengths) Sunlight or light from an incasdescent lamp through the prism
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/01/11 18:06 Dept/Chem, METU 10 Particle and wave nature of light Atoms in a hot body oscillate with a definite frequency, ν , E = nh ν , n = 1, 2, 3, .. h= 6.63x10 -34 J.s (Plank’s constant) Later, Albert Einstein postulated that light consists of quanta (photon) or particles of electromagnetic energy with energy E = h ν Photoelectric effect, Albert Einstein, 1905 750 0 C 1200 0 C h ν 3h ν 2h ν atom Max Plank (German Physicist) found a formula to explain the blackbody radiation from heated objects.
Image of page 10
11/01/11 18:06 Dept/Chem, METU 11 Photoelectric Effect Photoelectric Effect is the ejection of electrons from the surface of a metal when light shines on it. Results Electrons are ejected, only when ν exceeds threshold value of ν 0 Number of electrons emitted directly proportional to the intensity of light Kinetic energy of electron is linearly proportional to the ν E k = h ν
Image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern