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Unit 4 Electron Arrangement. Lesson 1: Waves and Light. “I can’t explain the different chemical properties of Elements”. The Puzzle of the Atom. Protons and electrons are attracted to each other because of opposite charges
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Unit 4 Electron Arrangement Lesson 1: Waves and Light “I can’t explain the different chemical properties of Elements”
The Puzzle of the Atom • Protons and electrons are attracted to each other because of opposite charges • Electrically charged particles moving in a curved path give off energy • Despite these facts, atoms don’t collapse
Wave-Particle Duality JJ Thomson won the Nobel prize for describing the electron as a particle. His son, George Thomson won the Nobel prize for describing the wave-like nature of the electron. The electron is a particle! The electron is an energy wave!
Electrons as Waves • In 1924, Louis de Broglie (French scientist) • suggested the way quantized electrons orbit the nucleus is similar to behavior of a wave • electrons can be seen as waves confined to the space around a nucleus • waves could only be certain frequencies since electrons can only have certain amounts of energy
The Electromagnetic Spectrum Wavelength/frequency/energy
What is it? • An electromagnetic wave consists of electric and magnetic fields which vibrates thus making waves. • The electromagnetic spectrum is the complete spectrum or continuum of waves including radio waves, infrared, visible light, ultraviolet light, X-rays and gamma rays
Radio waves • Low energy waves with long wavelengths • Includes FM, AM, radar and TV waves • Wavelengths of 10-1m and longer • Low frequency • Used in many devices such as remote control items, cell phones, wireless devices, etc.
Microwaves • The wavelength is shorter than radio, longer than light and infrared. • Wavelength 1 x 10 - 4 m to 1 x 10-1 m • First used in radar, now used in communication, medicine and consumer use (microwave ovens)
Invisible electromagnetic waves that are detected as heat Can be detected with special devices such as night goggles Used in heat lamps Higher energy than microwaves but lower than visible light Infrared waves
Visible Light • The portion of the electromagnetic spectrum that human eyes can detect • ROY G BIV (red, orange, yellow, green, blue, indigo, violet) • Red is the lowest frequency and violet is the highest frequency
Ultraviolet waves • Higher energy than light waves • Can cause skin cancer and blindness in humans • Used in tanning beds and sterilizing equipment
X-Rays • High energy waves • First discovered by Roentgen • Used in medicine, industry and astronomy • Can cause cancer
Gamma rays • Highest energy • Blocked from Earth’s surface by atmosphere
Long Wavelength = Low Frequency = Low ENERGY Short Wavelength = High Frequency = High ENERGY