Formula Unit of Ionic Compounds
Before we describe formula mass, we should know the meaning of 'formula unit' of an ionic compound.This is discussed below. An ionic compound is made up of an extremely large number of positively charged ions and negatively charged ions joined together. For example, sodium chloride is an ionic compound which consists of a large (but equal) number of sodium ions, ,and chloride ions,, so the actual formula of sodium chloride compound should be or , where tt is a very large number (see Figure 42). NaCl is the simplest formula of sodium chloride and not its actual formula.
The simplest combination of ions that produces an electrically neutral unit, is called a 'formula unit'of the ionic compound. The 'formula unit' of an ionic compound can be thought of as the smallest unit of that compound, it is the equivalent of a 'molecule'of the compound.The formula unit of sodium chloride compound is NaCl (which consists of one ion and one ion) (see Figure 43). The formula unit of ammonium sulphate is It consists of two ions and one ion.
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Atoms and Molecules - Notes
2. Monovalent Cations (Cations Having a Valency of 1+)
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3. Divalent Cations (Cations Having a Valency of 2+)
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4. Trivalent Cations (Cations Having a Valency of 3+)
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6. an example, let us give the significance of symbol C
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7. Formulae of Some Molecular Compounds
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9. Molecular Formulae of Some Common Elements
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10. Explanation of the Law of Conservation of Mass
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11. 2. A Negatively Charged Ion is Known as Anion
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13. As an example, let us give the significance of the formula H
2O
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14. Simple Ions and Compound Ions (Polyatomic Ions)
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21. Gram Atomic Mass And Gram Molecular Mass
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28. 1. A Positively Charged Ion is Known as Cation
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34. Divalent Anions (Anions Having a Valency of 2-)
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35. Molecular Masses of Some Common Elements
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37. Explanation of the Law of Constant Proportions
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39. Significance of the Formula of a Substance
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42. Symbols Derived from Latin Names of the Elements
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45. Valencies of Some Common Metal Elements Valencies of Some Common Non-Metal Elements
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46. Atomic Masses of Some Common Elements
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47. Writing Of Formulae Of Molecular Compounds
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50. Writing Of Formulae Of Ionic Compounds
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