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This article explains the characteristics of light waves, including wavelength, frequency, and amplitude. It also discusses the wave equation and Planck's equation. Additionally, it explores the electromagnetic spectrum and emission spectra of elements. The Bohr model of an atom and its relation to light emission are also covered.
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Electrons in Atoms Chap. 5
Light (electromagnetic radiation) A. Two components
Light (electromagnetic radiation) A. Two components • Electrical wave
Light (electromagnetic radiation) A. Two components • Electrical wave • Magnetic wave
Light (electromagnetic radiation) A. Two components B. Two natures
Light (electromagnetic radiation) A. Two components B. Two natures • Particle
Light (electromagnetic radiation) A. Two components B. Two natures • Particle • Wave
Light • Characteristics of a Light Wave
Light • Characteristics of a Light Wave • wavelength
Light • Characteristics of a Light Wave • wavelength The distance between successive wave crests
Light • Characteristics of a Light Wave • wavelength • frequency The time it takes a wave to pass a given point
Light • Characteristics of a Light Wave • wavelength • frequency • amplitude The height of a wave
Light • Characteristics of a Light Wave • wavelength • frequency • amplitude • speed
Light • Characteristics of a Light Wave • The Wave Equation
Light • Characteristics of a Light Wave • The Wave Equation • inverse relation of wavelength and frequency
Light • Characteristics of a Light Wave • The Wave Equation • inverse relation of wavelength and frequency • check the units
The Wave Equation c = λxυ
Self Check – Ex. 1 A light wave has a frequency of 2.6 x 1014 Hz. What is the wavelength?
Self Check – Ex. 2 What is the frequency of light with a wavelength of 0.0000072 m?
Light • Characteristics of a Light Wave • The Wave Equation • Planck’s Equation
Planck’s Equation E = hxυ h = 6.63 x 10-34 J·s
Self Check – Ex. 3 A light photon has 4.2 x 10-19 J of energy. What is the frequency of this light?
Self Check – Ex. 4 How much energy does a photon of orange light have (λ = 630 nm)? 109 nm = 1 m
Light • Characteristics of a Light Wave • The Wave Equation • Planck’s Equation • The Electromagnetic Spectrum
Electromagnetic Spectrum Long waves Short waves
Electromagnetic Spectrum Long waves Short waves Radio waves
Electromagnetic Spectrum Long waves Short waves Radio waves Micro-waves
Electromagnetic Spectrum Long waves Short waves Radio waves Infra-red Micro-waves
Electromagnetic Spectrum Long waves Short waves Radio waves Infra-red Micro-waves Visible
Electromagnetic Spectrum Long waves Short waves Radio waves Infra-red Ultra-violet Micro-waves Visible
Electromagnetic Spectrum Long waves Short waves Radio waves Infra-red Ultra-violet Micro-waves Visible X-rays
Electromagnetic Spectrum Long waves Short waves Radio waves Infra-red Ultra-violet Gamma rays Micro-waves Visible X-rays
Emission Spectra • Definition
Emission Spectrum: The various types of light given off when an atom is excited
Emission Spectra • Definition • Examples
Hydrogen’s Spectrum 400 nm 500 nm 600 nm 700 nm Note – only a few colors are present
Mercury’s Spectrum 400 nm 500 nm 600 nm 700 nm
Neon’s Spectrum 400 nm 500 nm 600 nm 700 nm
Emission Spectra • Definition • Examples • Explanation – Bohr’s Model
e- Bohr’s Model of an Atom
e- Bohr’s Model of an Atom Electrons orbit the nucleus (like planets orbiting the sun)
e- Bohr’s Model of an Atom Electrons must be in a specific orbit (never between orbits) n=1 n=2 n=3
e- Bohr’s Model of an Atom Electron wants to be in the lowest unoccupied level
e- Bohr’s Model of an Atom The energy of the electrons depends on the distance from the nucleus high energy low energy
Bohr’s Model of an Atom Light is emitted when electrons fall to lower energy levels e-
e- Bohr’s Model of an Atom Only certain sized falls are permitted.
Hydrogen’s Spectrum What is the energy for each line produced? 410 nm 486 nm 656 nm 434 nm
Hydrogen’s Spectrum What is the energy for each line produced? 410 nm 486 nm 656 nm 434 nm