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Structure and Bonding
This chapter will introduce the carbon atom
and the covalent bonds that join
carbon atoms together in organic molecules.
The most fundamental properties
of atoms and of covalent bonds will be introduced,
including hybridization,electronic structure,
molecular orbital theory and the shape of
organic molecules. The fundamental causes of
the physical properties exhibited by organic
molecules will also be introduced.
1. 1. Atomic Orbitals
What Is The Working Structure Of An Atom?
Each atom of a given element possesses a fixed number of protons, neutrons and electrons. The protons and neutrons comprise the nucleus and the electrons are located in discreet energy levels (quanta) from the nucleus. The nucleus is electrically positive and electrons are negatively charged. When carbon forms a covalent bond (two electrons are in each bond, represented by C-X, where X is any atom; see section 2.3), it uses electrons from the outermost shell. These electrons are conveniently described by their "shape" and distance relative to the nucleus.
What Are Atomic Orbitals And What Are Molecular Orbitals?
The space occupied by electrons is described by the term orbital. Different orbitals are described by their distance from the nucleus (the energy required to 'hold' the electron) as well as the three-dimensional configuration of their electrons. If the electrons are associated with the atom of a free element, they are said to be in atomic orbitals. Once bonds have been formed, the atomic elements become part of molecules, and theelectronic positions are described by molecular orbitals.