1. 1. What is an atomic emission spectra? 2. Why is Bohr’s model of the atom considered quantized? Question of the Day Day 1 1-6 The spectra (energy) given off when an atom’s electrons are excited. Electrons are found in specific energy levels.

2. 1. Amplitude affects __________. 2. Longer wavelengths = ______ frequencies lower brightness 3. High frequency = _____ energy and ______ wavelength High Short

3. Who demonstrated photons can move electrons? How?

4. 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.

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

6. 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. …

7. 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. …

8. 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.

10. DEFINE: energy level AND atomic orbital AND Read section 5.1 AND answer questions 1, 2, 4, and 5 on page 132 BINDER CHECKS!!!

11. What does it mean if something is quantized? Day 2 1-9

12. 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 …

13. 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:

14. 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.

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

16. Drawing: Day 2 1-9

17. Energy Source Absorbed Energy Energy Released

18. Energy within the atom? Increases away from the nucleus ENERGY

19. Radiant Acrostic RADIANTRADIANT

20. 1. In order to become excited an electron must _____________. 2. The most stable state for an atom is the ______ state. 3. Radiant energy = __________________ Question of the Day Day 3 1-10 4. Energy within an atom increases … absorb energy ground sun / electromagnetic radiation

21. h a

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

23. 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?

24. 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.

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

26. 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.

27. Friday 1-10 day 3

28. 1. If an electron absorbs energy it moves into an _______ state. 2. Almost immediately it falls back down to the _______ state. Question of the Day Day 4 1-13 excited ground

29. 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.

30. 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.

31. 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.

32. The Elusive Electron Evades Subatomic State Trooper! Werner Heisenberg Uncertainty Principle In 1927, he proposed the Uncertainty Principle speedlocation This states that it is impossible to know both the speed and location of an electron at the same time.

33. Why is it so hard to pinpoint the electron? To determine the speed and the location of an object, you must be able to SEE the object… light is bounced off the object when you see it. Light is made up of quanta or photons.

34. When photons hit a speeding car, the car is unaffected. But when a photon hits a speeding electron, the electron will move or change direction. So, if a photon hits an electron and the light bounces off it into your eyes, you will see where the electron was, but you won’t know how fast it was going at the time.

35. Heisenberg Explain the Heisenberg Uncertainty Principle. speedlocation It is impossible to know both the speed and location of an electron at the same time. What, am I speeding?

36. The New Atom…. location speed If you cannot know the exact location and speed of the electron, what is a scientist to do? region areas/zones of probability With the use of calculus, the region where the electron is most likely to be can be determined. These regions are called areas/zones of probability

37. pattern overlap standing The most likely location of an electron is described by a wave of probability. This type of wave is actually a set pattern that forms a 3-D shape within the space of the atom. This wave pattern does not overlap itself and is known as a standing wave.

38. Let’s now return to Bohr’s atomic model…

39. specific energy levels Bohr said that electrons are found in specific energy levels in an atom. Each energy level is a circle or sphere with a definite radius. …

40. average cloud Each energy level is a circle or sphere with a definite radius. … Bohr was close: What he thought as definite is actually the average radius. With quantum mechanics, the model of the energy level has expanded from a specific sphere to a region of probability that is like a cloud around the nucleus.

42. Quick Draw radiant energy Excited state wavelength electron cloud model Bohr

43. Radiant Acrostic RADIANTRADIANT

44. RADIANTRADIANT