1. Why is the energy in an atom said to be quantized? Question of the Day Day 4 1-4

If a light wave has a frequency (ν) of 3.0 * Hz, what is its wavelength? 1.0 * m REVIEW

2. Who demonstrated photons can move electrons? Compton AHHHH!

The relationship between frequency , wavelength ( ), and color to the energy of light:  , Color: red = low E, violet = high E E  : many photon punches E  : big gaps between consecutive photons.

Color: red = low E, violet = high E each color has its own energy color = type of light

The Effects of Different Photons: Microwaves: can’t feel Infrared: feel with skin, warms or burns. Visible light: see with eyes, heats when absorbed. Ultraviolet: can’t feel or see, affects cells – freckles, tan, burn, cataracts.

X-rays: can’t feel or see, pass through body, but absorbed by bones and dense matter. Gamma rays: can’t see or feel, affects cells, causes mutations in cells and molecules. The Effects of Different Photons: Ultraviolet: can’t feel or see, affects cells – freckles, tan, burn, cataracts.

Neils Bohr (bright) line spectrumH Tried to explain why each element has its own unique (bright) line spectrum. He studied H. specific energy levels orbitshell nucleus Using previous discoveries- Bohr hypothesized that an atom’s electrons are located in specific energy levels. Each energy level, aka orbit or shell is a set distance from the atom’s nucleus. …

jumpfall energy between … Electrons jump or fall from one energy level to another, while simultaneously gaining or losing energy. Electrons are not permitted to stop between energy levels. Neils Bohr orbitshell nucleus … Each energy level, aka orbit or shell. Is a set distance from the atom’s nucleus. …

Bohr’s Hypothesis In the line spectrum of an atom, Bohr saw specific colors.In the line spectrum of an atom, Bohr saw specific colors. Each specific color has a specific energy.Each specific color has a specific energy. That specific amount of energy is related to a specific distance from the nucleus.That specific amount of energy is related to a specific distance from the nucleus.

Ground vs. Excited States: ground closest stable An atom is in the ground state when its electrons fill the lowest possible energy levels that are closest to the nucleus. This is when the atom is most stable. gain jump exact amount An electron can gain energy and jump to a higher energy level. The electron must absorb an exact amount …

gain jump exact amount photon An electron can gain energy and jump to a higher energy level. The electron must absorb an exact amount … of energy to make a jump to a specific energy level. The energy that the electron gains comes from a photon. Ground vs. Excited States:

excited stable When an atom’s electrons are in higher energy levels, the atom is in an excited state and is less stable. fall released visibleor invisible light The atom prefers to be stable, so the electrons fall into lower energy levels that are not full. As the electrons fall, energy is released in the form of visible or invisible light.

atoms prefer… to be stable! to have low energy! to be in their ground state!

Energy within the atom? Increases away from the nucleus ENERGY

DEFINE: energy level AND atomic orbital AND Read section 5.1 AND answer questions 1, 2, 4, and 5 on page definitions and 4 questions Day 3 1-3

Radiant Acrostic RADIANTRADIANT

Day When do we treat light as a wave? As a particle? 2. How did Arthur Compton demonstrate that light can act as a particle?

If a light wave has a frequency (ν) of 3.0 * Hz, what is its energy? 2.0 * m Review-Style

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Quantum Mechanics Mr. Bohr was concerned with calculating and predicting the line spectra of elements. What happens when there is more than 1 electron?

Quantum Mechanics Mr. Bohr was concerned with calculating and predicting the line spectra of elements. He wondered how electrons move and where they can be found in atoms. Bohr’s ideas worked well for hydrogen with 1 electron. … What happens when there is more than 1 electron?

Quantum Mechanics Bohr’s ideas worked well for hydrogen with 1 electron. … He predicted the infrared and ultraviolet bands of hydrogen’s emission spectrum. The equations he used came from Classical Mechanics, a branch of physics that describes the movements and interactions that are large enough to see.

But… Alas.. Bohr could not predict the bright-line spectra. The laws of Classical Mechanics just don’t cut it for atoms and electrons.

Electrons are tricky… they and other subatomic particles like them have their own code of conduct… They behave differently than anything you may be able to see with your eyes or with any other object. New ideas needed to be looked into, and these new ideas became known as Quantum Mechanics.

Louis de Broglie wave properties Planck’slight One of the first to think that electrons possess wave properties. He reasoned that since waves can act as particles do (taken from Planck’s idea about light), then particles might behave as waves do.

For tiny subatomic particles… are important increases atom Wave properties are important. As the size of the moving object decreases, its wavelength increases. The wavelength for a tiny electron can be as large as an entire atom.

So how does an electron move in an atom? circularspherical Bohr (and maybe you too…) thought that they moved in circular or spherical orbits. matter-wave idea With de Broglie’s matter-wave idea, now we theorize that electrons vibrate around the nucleus in a.

Homework # 1