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Electron Energy Level Notes. Purpose of Lesson. learn the structure of atomic orbitals because they are basic to chemical bonding. Starting Question. Make a Venn diagram comparing the Rutherford model of the atom with the Bohr Model and the quantum orbital model. Starting Question.
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Purpose of Lesson • learn the structure of atomic orbitals because they are basic to chemical bonding.
Starting Question • Make a Venn diagram comparing the Rutherford model of the atom with the Bohr Model and the quantum orbital model.
Starting Question • How is preparing for a quiz similar to preparing for an athletic competition?
Electron Energy Level Notes • Electrons do not travel around the nucleus of an atom in orbits • They are found in energy levels at different distances away from the nucleus.(kind of like shells or layers--see picture on p. 87). • They cannot exist between energy levels(just like the rungs of a ladder).
Electron Energy Level Notes • Energy levels are broken up into sublevels: • There are at least 4 possible types of sublevels—given labels: s, p, d, or f • Only a certain number of electrons may exist in an energy level, but the number varies. It can be determined by: • # of electrons in level = 2 x (# of energy level)2
Electron Energy Level Notes • Therefore: • energy level 1 = 2 (1)2 = 2 • energy level 2 = 2 (2)2 = 8 • energy level 3 = 18 • energy level 4 = 32 • etc...
Electron Energy Level Notes • In each energy level, electrons fill sublevels in a certain order (see p. 95) • Level 1: • only has one s sublevel (a spherical shape) • 2 electrons may fit in this sublevel--each one has an opposite “spin”, allowing them to take up the same space • Pauli exclusion principle—no more than 2 electrons may be found in the same orbital (“orbital” means a particular location)
Electron Energy Level Notes • Level 2: • has two sublevels: s and p • 2 electrons in s • there are 3 different p orbitals, and may hold 2 electrons each—6 total. (look at shape on p. 95--imagine how they can fit together) • total of 8 overall in Level 2
Electron Energy Level Notes • Level 3: • has 3 sublevels: s, p, and d • 2 electrons in s • 6 electrons in p • there are 5 different d orbitals, and 2 electrons can fit in each—total of 10. (look at picture of d orbitals, imagine how they can fit together) • total of 18
Electron Energy Level Notes • Level 4: • has 4 sublevels: s, p, d , and f • 2 electrons in s • 6 electrons in p • 10 electrons in d • 14 electrons in f (7 different orbitals for f) • total of 32
Electron Energy Level Notes • The order that electrons fill up orbitals does not follow the logical order of all 1’s, then all 2’s, then all 3’s, etc. • They follow the order found on pg. 98.
Electron Energy Level Notes • An easy way to remember this is to use the periodic table--it is arranged to show how these orbitals are filled.
Electron Energy Level Notes • The first rule for filling orbitals is that only one electron will be put in each orbital of a sublevel until all of them are filled, and after that, they may be paired up until the sublevel is full. • This is called Hund’s rule.
Quantum Model of atom • The quantum model is more a concept than something you have to calculate. There are calculations, but for any atom larger than hydrogen, these calculations are very complex. • It tells us where the electrons are located around the atom and their energy level. That is important because electron location determines the behavior of the electron and the atom.
Heisenburg Uncertainty Principle • You cannot know an electrons velocity and location at the same time. • Determining where electron are and what they are doing is very difficult • electrons act like waves and particles at the same time. • They act a waves when we use them to take pictures, like light pictures. • They act like particles when they are used to move objects.
We can use quantum numbers to describe four important things about the electron • The principal quantum number indicates overall energy and usually indicates distance from the nucleus. • The shape of its orbital (Azemuthal quantum number) • how that orbital is oriented with other orbitals (Magnetic quantum number.) • Another factor is the spin of the electron (spin quantum number.)
The four quantum numbers. • The first is N (Can be 1 or 2 or 3 and so on.) • The second is L the azemuthal quantum number (0 to n-1) we substitute letters for the value of L 0 s, 1 p, 2 d, 3 f • the magnetic quantum number is M sub L. It depends on L (goes from -L to L) • Spin quantum number is M sub and has a value of either +- 1/2
Wave Particle Duality • At the level of the very small, waves are not just waves, they are also particles. • In addition, at the level of the very small, particles are not just particles, they are waves. • Examples, your eyes are using the particle nature of light to see and electrons create a wave that can interfere with other electron waves to make an image.