MOLECULAR AND STRUCTURAL FORMULAE
• Structural formula shows how the atoms in a molecule are bonded to each other.
• 3 types of structural formula:
– expanded structure
– condensed structure
– skeletal structure
eg : BUTANE, C4H10
EXPANDED STRUCTURE
•Expanded structures indicate how atoms are attached to each other. It shows every atom & type of covalent bond in the molecules but are not representations of the actual shapes of the molecules.
CONDENSED STRUCTURE
• Condensed Structure does not show single bonds between C and hydrogen atoms, but double and triple bonds are shown.
•Two or more similar groups bonded to the same atom and branches are inclosed in brackets and subscript numeral is used to indicate its number.
• Skeletal structure does not show C and H (shows only the carbon skeleton), but functional groups such as -OH,-NH2 must be shown.
• Bonds are represented as lines.
• Carbon atoms are at the beginning, corner and end of a line.
• Describes how the atoms of a molecule are arranged in space.
CLASSIFICATION OF C & H ATOMS
• Classification of C atom
i. primary (1o) carbon; carbon bonded to 1 C
ii. secondary (2o) carbon; carbon bonded to 2 C
iii. tertiary (3o) carbon; carbon bonded to 3 C
iv. quarternary (4o) carbon; carbon bonded to 4 C
• H atom atoms are classified base on the C atom bonded to it.
eg. Primary hydrogen is the hydrogen bonded to primary carbon.
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