■ Covalent bonds
► | Chemical bond formed through the sharing of electrons between two non-metal atoms. | |
► | During the formation of covalent molecules, each non-metal atom provides one or more electrons to be shared with other atom. | |
► | Through the electron sharing, each non-metals will achieve duplet or octet electron arrangement. |
► | The types of covalent bond formed depends on the number of pairs of electron shared between two atoms. | |||||||||||||
► | There are three types of covalent bond as shown in the table below.
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■ Single covalent bond
► | Sharing of a pair of electrons between two non-metal atoms. | |
► | Each non-metal atom contributes one electron for sharing to achieve a stable electron arrangement. | |
► | Example : hydrogen, H2; chlorine, Cl2; hydrogen chloride, HCl2; water, H2O; methane, CH4; ammonia, NH3; tetrachloromethane, CCl4 |
► | The animation below shows the formation of single covalent bond.
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■ Double covalent bond
► | Sharing of two pair of electrons between two non-metal atoms. | |
► | Each non-metal atom contributes two electron for sharing to achieve a stable electron arrangement. | |
► | Example : oxygen, O2; carbon dioxide, CO2 |
► | The animation below shows the formation of double covalent bond.
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■ Triple covalent bond
► | Sharing of three pair of electrons between two non-metal atoms. | |
► | Each non-metal atom contributes three electron for sharing to achieve a stable electron arrangement. | |
► | Example : nitrogen, N2 |
► | The animation below shows the formation of triple covalent bond in nitrogen molecule, N2.
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■ Formulae of covalent compounds.
► | Covalent compounds comprise element from group 14, 15, 16, and 17. (non-metal). |
► | A non-metal element M need x electrons to achieve stable electron arrangement. | |
► | A non-metal element N need y electrons to achieve stable electron arrangement. |
► | Thus, the formula of the covalent compound formed will be MyNx |
■ Number of electron to achieve stable electron arrangement
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► | Determine the number of electron needed to achieve stable electron arrangement. | |
► | Cross over the numbers of electron needed to achieve stable electron arrangement. | |
► | The animation below shows the way of predicting the formula of covalent compound.
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⇲ For exercise(objective and subjective), download for free on Android OS. | ||
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