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chemistry igcse acapprinted 48 · PDF 48
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Na has 1 electron in its valence shell while Cl has 7 electrons in its valence
shell. One Na atom loses 1 electron while 1 Cl atom gains 1 electron. This
forms NaCl, an ionic compound, with a stable electronic configuration.
• Properties of Ionic Compounds:
• Have high melting/boiling points (as the strong electrostatic forces in the
giant ionic lattice require a large amount of energy to break).
• Conduct electricity in molten or aqueous state, not as solids (as their ions can
move freely).
• Are soluble in water.
Covalent Bonding
• The type of bonding between two or more non-metal atoms is known as
covalent bonding.
• Non-metal atoms mutually share electrons amongst themselves to form a
stable electronic configuration
• One electron pair shared = Single covalent bond.
• Two electron pairs shared = Double covalent bond.
• Three electron pairs shared = Triple covalent bond.
• Covalent bonds are often graphically represented as dot-and-cross diagrams,
but these are different from the diagrams of Ionic bonding, e.g. C