Use Lewis diagrams to show how electrons are shared to form covalent bonds in compounds with the following atoms. Write the formulas.
a) Two hydrogen atoms attached to a carbon atom that also has one oxygen atom attached to it.
Answer (2)
The Lewis structure/diagram for CH2O (aka Formaldehyde) can be written in either of the following ways shown in the picture. The dots represent electrons in the valence shell of the atom (the outermost shell). The green dots are electrons that belong to the Oxygen atom, the blue belong to the Carbon atom, and the pink belong to the Hydrogen atoms. Covalent bonds are bonds between atoms where atoms share electrons with each other. Atoms bond because they obey the octet rule ( the rule states that most atoms of main-group elements tend to want 8 electrons in their valence shells). Oxygen has 6 valence electrons, Carbon has 4, and Hydrogen has 1. H does not follow the octet rule, but C and O do, so the atoms are arranged in this way so that the O and C atoms have a full octet of electrons in their valence.
The Lewis structure for the compound CHâ‚‚O (formaldehyde) shows a carbon atom bonded to two hydrogen atoms by single bonds and to one oxygen atom by a double bond. This arrangement allows the carbon and oxygen atoms to achieve full octets, while hydrogen achieves its duplet. The structure can be represented as H-C=O, with oxygen having two lone pairs of electrons.
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