Bonding
Bonding is something we do when we meet people to become friends. Bonding is also what atoms do with other atoms to become molecules.
We bond with people when we share food, atoms bond with atoms when they share electrons.
Yup, that’s enough of that analogy.
Covalent Bonding
A covalent bond is one that occurs between non-metal atoms.
Covalent bonding between non-metals occurs when two positive nuclei are held together by their electrostatic attraction to a shared pair of electrons.
Some elements of the periodic table exist in pairs of atoms. These are called diatomic molecules. They include: Hydrogen, Oxygen, Nitrogen, Fluorine, Chlorine, Bromine and Iodine.
Covalent Molecules
Covalent bonding can create two types of structure: covalent molecular structures and covalent networks.
Covalent molecular structures are small molecules with low melting and boiling points. You need to be aware of the different shapes these molecules can take: Linear, Angular, Trigonal pyramidal and Tetrahedral.
The intramolecular bonds (those within the molecule) are strong in covalent molecular substances.
The intermolecular bonds (those which occur between molecules) are weak between covalent molecular substances.
The melting and boiling points of covalent molecular substances are low because energy is only required to break the weak intermolecular bonds between molecules.
Covalent molecular substances cannot conduct electricity but can dissolve in water.
Covalent Networks
Covalent networks are large, strong structures formed with covalent bonds. Examples of covalent networks include diamond and graphite.
Covalent networks have very high melting and boiling points because the intramolecular bonds between atoms are very strong and a large amount of energy is required to break them.
Covalent networks cannot conduct electricity, apart from graphite.
Covalent network structures cannot dissolve in water.
Ionic Bonding
A ionic bond is one between a metal and a non-metal.
Ionic bonds occur when a bond is formed between a metal and a non-metal due to the electrostatic attraction between oppositely charged ions. One atom will donate their electron(s) to the other atom to allow them both to have a full outer shell, creating one positive and one negative ion. The electrostatic attraction between these ions is called ionic bonding.
The structure of these compounds is called an ionic lattice structure.
The melting and boiling points of ionic compounds are high because the electrostatic force between positive and negative ions in ionic bonding is very strong.
Ionic compounds dissolve in water.
When dissolved in water or when molten, ionic compounds can conduct electricity because the ions are free to move.
Key Points!
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Covalent Bonding
A covalent bond is one that occurs between non-metal atoms.
Covalent bonding between non-metals occurs when two positive nuclei are held together by their electrostatic attraction to a shared pair of electrons.
Some elements of the periodic table exist in pairs of atoms. These are called diatomic molecules.
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Covalent Molecules
to be aware of the different shapes these molecules can take: Linear, Angular, Trigonal pyramidal and Tetrahedral.
The intramolecular bonds (those within the molecule) are strong in covalent molecular substances.
The intermolecular bonds (those which occur between molecules) are weak between covalent molecular substances.
The melting and boiling points of covalent molecular substances are low because energy is only required to break the weak intermolecular bonds between molecules.
Covalent molecular substances cannot conduct electricity but can dissolve in water.
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Covalent Networks
Covalent networks have very high melting and boiling points because the intramolecular bonds between atoms are very strong and a large amount of energy is required to break them.
Covalent networks cannot conduct electricity, apart from graphite.
Covalent network structures cannot dissolve in water.
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Ionic Bonding
A ionic bond is one between a metal and a non-metal.
Ionic bonds occur when a bond is formed between a metal and a non-metal due to the electrostatic attraction between oppositely charged ions.
The structure of these compounds is called an ionic lattice structure.
The melting and boiling points of ionic compounds are high because the electrostatic force between positive and negative ions in ionic bonding is very strong.
Ionic compounds dissolve in water.
When dissolved in water or when molten, ionic compounds can conduct electricity because the ions are free to move.