Br: Which subatomic Particle is responsible for the characteristics and behavior of an atom?

1. Br: Which subatomic Particle is responsible for the characteristics and behavior of an atom? Electron EQ: What did Erwin Schrodinger contribute to our modern atomic Theory? He determined that electrons are located in cloud-like orbitals and used quantum math to describe the shapes and locations of those orbitals.

2. we will . . . • SC3 Students will use the modern atomic theory to explain the characteristics of atoms. • b. Use the orbital configuration of neutral atoms to explain its effect on the atom’s chemical properties.

3. Empedocles’ Elements Ancient Greeks believed all substances were made of essential “elements”.

4. DEMOCRUTUS’ “ATOMA” Democritus created the idea that all matter is made up of various imperishable, indivisible units, which he called atoma. This idea was soon rejected and forgotten.

5. DALTON’S ATOM Many years later, Dalton again proposed the idea of that all matter is made of indivisible and indestructible atoms. Dalton’s model of the atom was one solid sphere.

6. THOMSON’S “PLUMB PUDDING” Thomson tried to show how electrons were situated in the atom. He proposed in a model in which the atom was a positively charged ball with negatively charged electrons stuck onto the surface. It was called the “plum pudding” model, since the electrons in the atom resembled the raisins in a plum pudding.

7. RUTHERFORD’SSPINNING ELECTRONS Ernest Rutherford's experiments led him to describe the atom as having a relatively small but heavy nucleus with electrons in orbit around it.

8. BOHR’S ENERGY LEVELS He suggested that electrons could only have certain motions: • The electrons travel in orbits at specific distances from the small nucleus. These distances were called energy levels.

9. Bohr Moel • First energy level holds 2 electrons • Second energy level holds 8 electrons • Third energy level holds 18 electrons • Fourth energy level holds 32 electrons • And so on . . . • A clear default of the Bohr model is that it does not clearly explain the movement and location of electrons in larger atoms containing multiple electrons.

10. De Broglie • He added to Bohr's model of the atom by reasoning that, since light could act like a particle, an electron could act like a wave.

11. schrodinger • Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. Used quantum math to show the probability of an electron being in a given area, and he called those areas electron clouds.

12. Electron Location:The Quantum Model of the Atom 5.1

13. Atomic Orbitals and Quantum Numbers • Quantum numbers completely describe electron orbitals and the specific location of an electron. • Quantum numbers specify the properties of atomic orbitals and the properties of electrons in orbitals. • There are four quantum numbers.

14. Principle Quantum Number • The principle quantum number (n) indicates the main energy level occupied by the electron. • n can only be a positive whole number 1-7. • Small n values indicate close proximity to the nucleus. Large n values indicate that an electron is farther from the nucleus.

15. Angular Momentum Quantum Number • The angular momentum quantum number (l) indicates the shape of the orbital. • For a given energy level, the number of angular momentum values allowed is equal to n • The angular values allowed are 0 through n-1. • The angular momentum quantum number defines s, p, d, and f orbital shapes.

16. Orbital Shape • s -- sphere • p -- dumbbell • d --double dumbbell dumbbell & doughnut • f -- very complex shape

17. Magnetic Quantum Number • The magnetic quantum number (m) indicates the orientation of an orbital around the nucleus. It describes how the orbital lies on an axis x, y, z. • s orbitals only have 1 orientation in space. • p orbitals can have 3 orientations in space. • d orbitals can have 5 orientations in space. • f orbitals can have 7 orientations in space.

18. Spin Quantum Number • The spin quantum number (s) indicates the direction of an electron’s spin. • Electrons are thought of as having two spins. (clockwise & counter clockwise) • There are only two possible values for the spin quantum number, +1/2 and -1/2.

19. Properties of Light: Wave Particle Duality • Scientists now know that light can behave both as a stream of particles or as a wave of energy. • A single particle of light is called a photon. • When we speak of light as a wave, we call it electromagnetic radiation. • The electromagnetic spectrum shows that light can have a wide range of wavelengths and frequencies.

20. Electromagnetic Spectrum Entire Spectrum Visible Spectrum

21. Characteristics of a Wave • Waves are important to study in order to understand the properties of light: • Wavelength (l) – the distance between two corresponding points on adjacent waves. • Frequency (n) – the number of waves that pass a point in a specific time • Speed (c) – all electromagnetic radiation moves at a constant speed of 3.0 x 108 m/s “speed of light” • The speed of light, wavelength, and frequency are related c = nl

22. Characteristics of a Wave • Relationships of wave properties • Wavelength and frequency are indirectly proportional • Wavelength and energy are indirectly proportional • Frequency and Energy are Directly proportional Long wavelength Low Energy Low Frequency Short Wavelength & High Energy & High Frequency

23. The Photoelectric Effect • Electrons absorb energy from electromagnetic radiation and move from the low energy ground state to the high energy excited state. • “Excited” electrons move back to the ground state by releasing photons of light.

24. Element Identification Each photon of light released during the photoelectric effect corresponds to a specific wavelength and frequency of light resulting in an emission spectrum unique to individual elements. Emission Spectrum

25. Emission Spectrum Identification Identify the unknown element based on its emission spectrum. Unknown element • Hydrogen • Carbon • Nitrogen

26. Emission Spectrum Identification Unknown element • Chromium • Iron • Titanium Identify the unknown element based on its emission spectrum.

27. Emission Spectrum Identification Unknown element • Vanadium • Gold • Zirconium Identify the unknown element based on its emission spectrum.

28. Spectrum Tubes

29. Flame Test Lab • Pre-Lab Questions • Purpose • Data Table • Post-Lab Questions • (1, 2, 3, 4a, 4b, 4c, 4d, 5) • E = hn h is 6.63 x 10 -34

30. What are “excited” and “ground” states? The ground state is an electron’s low energy position. The excited state is an electron’s high energy position.

31. Which subatomic Particle is responsible for the characteristics and behavior of an atom? ElectronWhat did Erwin Schrodinger contribute to our modern atomic Theory? He introduced the Electron Cloud Theory

32. How is an emission spectrum produced? Electrons gain energy to move the to excited state. They release energy in the form of a photon to move back to the ground state. Which quantum number indicates the shape of the orbital occupied by an electron?

33. How is an emission spectrum produced? Electrons gain energy to move the to excited state. They release energy in the form of a photon to move back to the ground state.Which quantum number indicates the shape of the orbital occupied by an electron? 2nd quantum number-Angular Momentum (l)

34. The Photoelectric Effect is used to create: Emission Spectra Colored Light Spectrums Electric Gas Tubes Colored Flames-Flame Test Fireworks Which quantum number indicates the energy level of the orbital occupied by an electron? 1st quantum number-Principal Quantum Number