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Covalent Bond – How Atoms Come Together to Form a Molecule

by Georgina Cornwall, PhD
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    00:00 Buffers. So to begin, lets look at covalent bonds. Covalent bonds involve sharing of electrons.

    00:10 So each atom has equal interest in the electrons between them. A single covalent bond involves the sharing of one pair of electrons. For example here, we'll look at hydrogen gas.

    00:24 Hydrogens alone have a single electron in the outermost shell which gives them a valence of one because ideally to fill that innermost shell they would like two electrons. So, hydrogen will get together with another hydrogen and they will each share the pair of electrons so that the octet rule is satisfied and each has a stable outer shell with two electrons.

    00:52 Next, we'll look at covalent bonds sharing two pairs of electrons or a double covalent bond.

    01:01 In this case we'll use oxygen as an example. Oxygen has six valence electrons which means that to satisfy the octet rule, it would like to have another two electrons in its valence shell.

    01:18 It can satisfy the octet rule simply by sharing two electrons with one other oxygen.

    01:25 So oxygens now have two pairs of shared electrons in the valence shell. Four of their own, two pairs of shared. That equals eight. Satisfies the octet rule. So, oxygen and oxygen or oxygen gas is quite stable. Now, lets look at a triple covalent bond. For example, nitrogen has five valence electrons.

    01:51 In order to be satisfied, it would like to have three additional electrons. So a triple covalent bond involves the sharing of three pairs of electrons. It is the strongest of the bonds that we will be looking at in this course. So, nitrogens adding the three more electrons sharing with another nitrogen finally have eight electrons in the valence shell. Three pairs of electrons form a stable molecule of nitrogen gas. Nitrogen is really hard to break apart. In fact there are only a hundred species of nitrogen fixing bacteria that are able to separate nitrogen gas. The two nitrogen molecules and break that triple bonding arrangement to bring all of the nitrogen that we have in the plants that grow on earth and thus consume ourselves. So nitrogen originates from nitrogen gas in the atmosphere. The bond is really hard to break because its a triple covalent bond.

    02:52 The strongest of the biological bonds.


    About the Lecture

    The lecture Covalent Bond – How Atoms Come Together to Form a Molecule by Georgina Cornwall, PhD is from the course Introduction to Cell Biology.


    Included Quiz Questions

    1. …covalent bonding category.
    2. …ionic bonding category.
    3. …hydrophobic interactions.
    4. …hydrogen bonding category.
    5. …van der Waals forces.
    1. The nitrogen gas can be easily broken down into individual atoms at the standard room temperature due to weak bonding between the atoms.
    2. The covalent bonding involves the sharing of electron pairs between the participating atoms.
    3. The nitrogen gas involves the sharing of three electron pairs between the two nitrogen atoms to create a highly stable molecule.
    4. In methane molecule, the carbon atom forms four covalent bonds with four atoms of hydrogen to satisfy the octet rule.
    5. The covalent bonding leads to the formation of stable molecules.

    Author of lecture Covalent Bond – How Atoms Come Together to Form a Molecule

     Georgina Cornwall, PhD

    Georgina Cornwall, PhD


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