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- 1If a beam of red light has a wavelength of 650 nm, how much energy (in J) does this red light have?1. convert
2. c = yv
3. E=hv - 2Green light has lower energy than orange light?False
- 3If an electron falls a relatively short distance, light of relatively low energy would be emitted.True
- 4Why does an excited electron naturally fall towards the nucleus?electrons are attracted to nucleus (negative attracted to positive)
- 5Fluorescent substances only fluoresce (emit visible light) when________ light shines on the object.ultra violet
- 6When electricity is sent through an emission tube filled with hydrogen gas, distinct energies of light are emitted. Thus, a bright line or emission spectrum is obtained. Explain how this emission spectrum gives experimental evidence for the concept that the electron in hydrogen can exist in only distinct energy levels.• The emission spectrum of hydrogen consists of distinct lines. Thus, distinct energies of light are emitted.
• Distinct energies can be emitted only when the electron loses distinct amounts of energy.
• Thus, the electron must be limited in what “jumps down” it is allowed to make.
• Thus, the electron must be limited in what energies it can have. (The energies of the electron are quantized.)
• Saying this in another way: The electron in a hydrogen atom can only exist in distinct energy levels. - 7When you see an object as red, it is because ...all colors except red are absorbed
- 8Why is the sky blue?The atmosphere scatters short wavelength light more easily than longer wavelengths. Thus, blue (and violet) light is scattered the most.
- 9Explain why a black shirt gets hotter in the sun than a white shirt. (What is absorbed? What is emitted? What happens to e’s?)• A black shirt absorbs all visible colors of light (reflects none). Thus, electrons are excited into higher energy levels.
When electrons “fall” back down to lower energy levels, heat can be emitted. Thus, the shirt gets hotter.
• A white shirt absorbs no visible colors of light (reflects all). Thus, the electrons cannot be excited, so no heat is emitted.
• NOTE: Heat is also released by the sun. Thus, a white shirt does get somewhat hotter because heat is directly hitting it. - 10What does an orbital (or electron cloud) represent? How is an orbital different from an orbit?• An orbital is a region where there is high probability of finding the electron.
• An orbit has a defined path by which the electron travels.
• An electron in an orbital does not travel in a defined path. There is no way to predict with certainty where the electron
will be in the future. One can only know the probability of finding it in a particular region. - 11Draw a representation of a typical “s” orbital, “p” orbital and a “d” orbital. How many orientations are there of each type?
- 12Describe the photoelectric effect.When light is shone on metal, electrons will only be ejected if the light has the minimum energy required for that metal.
(For example, one metal might require yellow light—another might require uv light.) - 13How does the photoelectric effect support the conclusion that light can have properties of particles?In order for an electron to be emitted, the needed light energy must hit at the exact location of the electron. Thus the light
must have “packets of energy” (with at least the needed minimum energy) that hit each electron. This means that light is
acting like a particle (has a distinct location). We call these particles of light, photons.
Note: If one increases the intensity of the light, this only increases the number of photons, so this increases the number of
electrons emitted. However, if none of the photons have the minimum energy required, no electrons are emitted. - 14What experimental evidence gives support for the concept that electrons have properties of waves?• Electrons diffract when sent through the holes in a crystal. (Get a diffraction pattern—ripples)
• Electrons show interference patterns when sent through two holes. (Diffraction patterns interfere with each other.) - 15What are the differences between a particle, wave and wave-packet? (Discuss knowledge of location and energy of each.)Particle: Has defined location, but energy (momentum) is uncertain
Wave: Has a defined energy (has an exact wavelength), but its location is uncertain
Wavepacket: This is a representation of something that has wave and particle properties (wave-particle duality). Thus,
there is some uncertainty of both the location and the energy of a wave packet. - 16What does the Heisenberg uncertainty principle state?Heisenberg uncertainty principle states that one cannot simultaneously know both the location and energy of anything
with certainty. - 17How do electrons in atoms satisfy the uncertainty principle?All electrons in atoms must satisfy the uncertainty principle because they have properties of waves. For an electron in an
orbital, one knows the energy precisely, but the location is somewhat uncertain. (Only know the probable location of e−) - 18How many electrons can fit in the third main energy level?18
- 19What is another name for a row?Period
- 20What sublevel should become filled after the 5s sublevel is filled?4d
- 21What is the maximum number of electrons that can fit in any one orbital?2 e-
- 22Why do the electrons prefer to be unpaired?Electrons are all negative, so they repel each other. Thus, if available, electrons will spread out into another orbital of the
same energy. (Hund’s Rule) - 23Hund's ruleif available, electrons will spread out into another orbital of the
same energy.
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- 10th grade Chemistry (Electron Configuration, Periodic Table) FlashCards sobre Quiz, criado por Stephanie Michael em 16-01-2018.
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- Stephanie Michael
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