To define how a covalent bond forms. To apply the octet dominance to covalent compounds

You have already seen instances of substances that contain covalent bonds. One substance discussed previously was water (\(\ceH2O\)). You can tell native its formula the it is no an ionic compound; that is not created of a metal and a nonmetal. Consequently, its properties are various from those that ionic compounds.

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Electron Sharing

Previously, we discussed ionic bonding wherein electrons have the right to be moved from one atom to another so the both atoms have actually an energy-stable outer electron shell. Because most filled electron shells have actually eight electron in them, hunterriverpei.comists called this propensity the octet rule. However, there is another means an atom can accomplish a full valence shell: atoms can share electrons.

This concept can be portrayed by using two hydrogen atoms, every of which has a solitary electron in the valence shell. (For little atoms such together hydrogen atoms, the valence covering will be the an initial shell, i beg your pardon holds just two electrons.) We have the right to represent the two individual hydrogen atoms as follows:


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The Lewis chart of two hydrogen atom sharing electrons looks prefer this:


This relenten of molecules is simplified more by utilizing a dash to represent a covalent bond. The hydrogen molecule is then stood for as follows:


Each fluorine atom contributes one valence electron, making a solitary bond and also giving each atom a complete valence shell, i beg your pardon fulfills the octet rule:


The circles show that every fluorine atom has actually eight electrons approximately it. As with hydrogen, we deserve to represent the fluorine molecule with a dash in location of the bonding electrons:



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In this molecule, the hydrogen atom does not have actually nonbonding electrons, while the fluorine atom has actually six nonbonding electrons (three lone electron pairs). The circles display how the valence electron shells are filled because that both atoms.

Example \(\PageIndex1\)

Use Lewis diagrams to show the development of the following:

Cl2 HBr


a. When two chlorine atoms form a chlorine molecule, they share one pair that electrons. In Cl2 molecule, each chlorine atom is surrounding by one octet variety of electrons.

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The Lewis diagram because that a Cl2 molecule is similar to the one because that F2 (shown above).