Atoms in a Molecule Are Held Together by Chemical Bonds

Atoms in a Molecule Are Held Together by Chemical Bonds 

Chapters 1 and 2 dealt primarily with the electronic structure of isolated atoms of the various elements. With the exception of the noble gases, however, it is the molecule, not the individual atom, that is the basic building block of materials in nature. Even elements that occur naturally in their pure state are generally found in molecular form. For example, the oxygen and nitrogen in the atmosphere are made up of the diatomic molecules O2 and N2, not discrete O and N atoms. In Chapter 3, we begin our study of molecules and the chemical bonds that hold them together. 

To understand the nature of a chemical bond let s examine bonding in the simplest molecule, H2. If we could place a large number of individual H atoms in a container, they would quickly pair up to form H2 molecules. This process would release a large amount of energy because the energy of two hydrogen atoms is lower when they are bonded together as a molecule than when they exist as separate atoms. 

2 A Covalent Bond Involves the Sharing of Electrons Between Atoms in a Molecule 

The development of the periodiA Si O onE iDS elSllSilliSiZ CIdStX gave chemists a rationale for molecule and compound formation. This explanation, formulated by Gilbert Lewis, is that atoms combine in order to achieve a more stable electron configuration. Maximum stability results when an atom is isoelectronic with 

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