Unit 7- Quantum Chemistry and Electron Configurations

Question 1

What is a wave?

Answer 1

• A wave is a continuously repeating change or oscillation in matter or in a physical field
• Consists of oscillations in electric and magnetic fields that travel through space
• Visible light, X rays, and radio waves are all forms of electromagnetic radition

light is a wave

Question 2

What is the electromagnetic spectrum?

Answer 2

• The range of frequencies and wavelengths of electromagnetic radiation
• A continuous range of radiant energy (also called electromagnetic radiation)

Question 3

Wavelength

Answer 3

• is the distance between identical points of successive waves

weird upside down y symbol

Question 4

Amplitude

Answer 4

the vertical distance from the midline of a wave to the peak or trough

Question 5

Frequency

Answer 5

the number of waves that pass through a particular point in 1 second

Symbol: u

Question 6

Hz

Answer 6

• Hertz
• SI unit for frequency: Hz=1 cycle/s

Question 7

What is the formula for the speed of a wave?

Answer 7

Frequency x Wavelength

Question 8

How is color determined?

Answer 8

• The color of light is determined by its wavelength or frequency
• White light is a mix of all the colors of visible light

Question 9

What makes an object appear colored?

Answer 9

• When an object absorbs some of the wavelengths of white light and reflects others, it appears colored
• The observed color is predominatly the colors reflected or transmitted

Question 10

Electromagnetic Spectrum facts slide

Answer 10

• visible light comprises only a small fraction of all the wavelengths of light
• Visible light extends from the violet end of the spectrum at about 400 nm to the red end with wavelengths about 800 nm (beyond these extremes, electromagnetic radiation is not visible to the human eye)

Question 11

Wavelength energies

Answer 11

• Short wavelength (high-frequency) light has higher energy
• radiowave light has the lowest energy
• gamma ray light has the highest energy

high-energy electromagnetic radiation can potentially damage biological

Question 12

Behavior of Waves

Refraction

Answer 12

bending of light waves when passing between media of different densities (ex. air to water)

Question 13

Diffraction

Answer 13

bending of light waves as they pass around the edge of an object o through narrow openings

Question 14

interference

Answer 14

interaction of waves in which amplitudes either reinforce (constructive) or cancel (destructive)

Question 15

refraction

Answer 15

• angle of refraction depends on wavelength
• short wavelength beds the most

Question 16

What is the doppler effect?

Answer 16

• Motion-induced shift of frequency (ex. pitch of a police siren or train whistle changes when moving toward you/away from you)
• Red shift: light from objects moving away is shifted to longer wavelengths
• light from distant glaxies is red-shifted, consistent with Big Bang theory

Question 17

Max Planck and Quantum Theory

Answer 17

• Max Planck proposed particle-like properties of light… particles of radiant energy=quanta
• Quantum theory: based on the idea that energy is absorbed and emitted in discrete quanta

Question 18

quantized

Answer 18

having discrete values that are restricted to whole-number multiples of a specific base value
-packet of radiation called a quantum or a photon

Question 19

The energy of a quantum of radiation is:

Answer 19

• E=hv or E=hc / wavelength
• h=6.6260755x10^-34 Jxs (Planck’s constant)

Question 20

quantized vs continuum states

Answer 20

• Quantized states are discrete energy levels with no in between (electrons)
• Continuum states have smooth transition between levels