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Unformatted text preview: Organic Chemistry Chapters 1-5 Chapter 1 Introduction and Review 1-1 The origins of Organic Chemistry Organic chemistry is defined as the chemistry of carbon compounds These compounds are important because Carbon forms strong bonds to other carbon atoms and to a wide variety of other elements Chains and rings of carbon atoms can be built up to form an endless variety of molecules. Literally, organic means derived from living organisms. People used to accept Vitalism: the belief that natural products needed a vital force to create them This is no longer accepted (disproved in the early nineteenth century) because chemists found that organic compounds could be synthetically produced, therefore never having a life force Not all Carbon containing molecules are organic, however, most are. 1-2 Principles of Atomic Structure 1-2A Structure of the Atom-Protons and neutrons have about 1800 times the mass of an electron (1/2200 amu)-Atoms with the same number of protons but different numbers of neutrons are called isotopes 1-2B Electronic Structure of the Atom-Electrons show both wave and particle properties, however, they behave more like waves than particles-The Heisenberg uncertainty principle states that we can never determine exactly where the electron is, however, we can determine the electron density : the probability of finding the electron in a particular part of the orbital .-An orbital is an allowed energy state for an electron-Atomic orbital are grouped into different shells at different distances from the nucleus. -Each shell is identified by a principal quantum number, n.-The first energy shell can hold 2 electrons, the second 8, -the first electron shell contains the 1s orbital.-S orbital are spherically symmetrical and therefore non directional.-Electron density is highest at the nucleus and decreases going outward.-the 1s orbital has an electron density that is greatest when it is closest to the nucleus and decreases going outward.-the second electron shell contains a 2s and 2p orbital-the 2s orbital has an electron density that is farther away from the nucleus beyond the node.-there are three 2p x orbital, 2p y orbital, and the 2p z orbital, named according to their direction on a Cartesian coordinate system.-The 2p orbital are slightly higher in energy than the 2s orbital-orbital with the same energy are called degenerate orbital-The Pauli exclusion principle tells us that each orbital can hold a maximum of two electons provided that their spins are paired. 1-2C Electron Configurations of Atoms-The Aufbau principle tells us how to build up the electronic configurations of an atoms ground state-Afbau means Building up in German-An atoms ground state is its most stable state-This principle tells us that we fill the orbital with the lowest energy first-Hunds rule states that when there are two or more orbital of the same energy, electrons will go into different orbital rather than pair up in the same orbital....
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