Chapter 07 - CHEMISTRY The Molecular Science Chapter Seven...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
CHEMISTRY The Molecular Science Chapter Seven Electron Configurations and the Periodic Table
Background image of page 1

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

View Full DocumentRight Arrow Icon
Electromagnetic Radiation Consists of electric and magnetic fields oscillating in perpendicular planes. Travel at the same speed in a vacuum, c, speed of light. Electromagnetic wave is described in terms of wavelength – distance between adjacent crests (nm, μm). frequency – number of waves passing a point in a second (s -1 , Hz). amplitude – height of the crest (intensity).
Background image of page 2
Wavelength –Frequency – Amplitude
Background image of page 3

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

View Full DocumentRight Arrow Icon
Electromagnetic Spectrum
Background image of page 4
Frequency is related to wavelength: νλ = c c = speed of light = 2.998x10 8 m/s ν = frequency (s –1 ) λ = wavelength (m) Practice Problem 7.1 p. 275 A laser developed for use with digital video disc (DVD) players has a wavelength of 405 nm. Calculate the frequency of this radiation in hertz (Hz). 1 nm = 1x10 –9 m
Background image of page 5

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

View Full DocumentRight Arrow Icon
Black Body Radiation − emission spectrum of a heated object. Planck: an atom in a hot object emits light in units of quanta (photons). Light is quantized Quantum Theory. E quantum = hν radiation h = Planck’s constant = 6.626x10 –34 Js
Background image of page 6
E = hν ν = c/λ E = hc/ λ The energy per quantum (photon) of radiation increases as the wavelength gets shorter. Practice Problem 7.2 p. 277 (Refer to Figure 7.1 p. 274) Which has more energy, a) One quantum of microwave radiation or one quantum of ultraviolet radiation? b) One quantum of blue light or one quantum of green light?
Background image of page 7

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

View Full DocumentRight Arrow Icon
Photoelectric Effect The emission of electrons by substances, such as metals, when light of a certain wavelength falls on their surfaces . There is a threshold wavelength below which no photoelectric effect is observed, no matter how bright or intense the light is. Different metals require light of different energies to emit electrons. Einstein renamed a quantum = photon. Photons of different λ have different energy. E min = hν is the minimum energy of light to observe emission of electrons.
Background image of page 8
Photoelectric Effect
Background image of page 9

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

View Full DocumentRight Arrow Icon
Photons A photon = unit of electromagnetic energy. Photons have both particle and wave properties (dual nature of light. Massless particle behavior – photoelectric effect. Wave behavior – diffraction.
Background image of page 10
Diffraction patterns – wave nature of light When waves of light pass through adjacent narrow slits, the waves become scattered and spread out. They can interact destructively or constructively to produce dark or light spots.
Background image of page 11

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

View Full DocumentRight Arrow Icon
If a high voltage is applied to a gaseous element at low pressure, the atoms absorb energy and become excited. The excited atoms then emit the extra energy as radiation. Spectrum – distribution of intensities of wavelengths or frequencies of EM radiation emitted or absorbed by an object. Characteristic of a specific emitting substance.
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 69

Chapter 07 - CHEMISTRY The Molecular Science Chapter Seven...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online