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Types of chemical formula:
Empirical Formula: This gives the simplest whole-number ratio of atoms in a compound. For example, the empirical formula of hydrogen peroxide (H₂O₂) is HO.
Molecular Formula: This provides the exact number of each type of atom in a molecule. For example, the molecular formula of glucose is C₆H₁₂O₆.
Structural Formula: This shows how atoms are arranged and bonded together in a molecule. There are different types of structural formulas, including:
Lewis Structures: Depict the bonding between atoms of a molecule and the lone pairs of electrons.
Condensed Structural Formulas: Show the arrangement of atoms in a molecule in a more compact form than full structural formulas.
Skeletal Formulas: A simplified representation showing the bonding between carbons in organic compounds.
Ionic Formulas: These show the ratio of ions in a compound. For instance, the formula for sodium chloride is NaCl, indicating a 1:1 ratio of sodium ions to chloride ions.
Components of the chemical formula:
Element Symbols: Each element is represented by a one- or two-letter symbol. For example, H for hydrogen, O for oxygen, and Na for sodium.
Subscripts: Numbers are written at the lower right of element symbols to indicate the number of atoms of that element in the molecule. For example, in H₂O, the subscript 2 indicates there are two hydrogen atoms.
Coefficients: Numbers placed before the formula to indicate the number of molecules. For instance, 2H₂O means there are two molecules of water.
Parentheses: Used to indicate a group of atoms that behave as a single unit in a compound. For example, in calcium phosphate, Ca₃(PO₄)₂, the parentheses group the phosphate ions.
Charges: For ions, the charge is shown as a superscript at the end of the formula. For example, Na⁺, Cl⁻, SO₄²⁻.
Examples:
Water (H₂O): Two hydrogen atoms and one oxygen atom.
Carbon Dioxide (CO₂): One carbon atom and two oxygen atoms.
Sulfuric Acid (H₂SO₄): Two hydrogen atoms, one sulfur atom, and four oxygen atoms.
Methane (CH₄): One carbon atom and four hydrogen atoms.
