Covalent Molecules

Covalent Molecules

As we saw in our discussion of valence bond theory, covalent bonds involve the sharing of electrons between atoms rather than the transfer of electrons from one atom to another. Equation 3 depicts the formation of a covalent bond between a hydrogen atom and a chlorine atom.

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Exercise 3 What is the valence shell electron configuration of the hydrogen in HCl? What is the valence shell electron configuration of the chlorine?

Exercise 4 If the bond in a hydrogen chloride molecule were ionic, i.e. if the hydrogen transferred its valence electron to the chlorine, what would the valence shell electron configuration of the hydrogen be? What would the valence shell electron configuration of the chlorine be?

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In contrast to ionic compounds, covalent molecules may be gases, liquids, or solids. Those that are solids generally have melting points below 300^oC. Furthermore, aqueous solutions of most covalent molecules do not conduct a current. There are some notable exceptions however. HCl is one.