Compounds (OCR GCSE Chemistry A (Gateway Science Suite)): Revision Notes

1.1.2 Compounds

Properties: Compounds have chemically different properties from the elements that compose them.

Examples:

Water (H₂O):

• Elements: Hydrogen, Oxygen
• Number of Elements: 2
• Atoms: 2 Hydrogen atoms, 1 Oxygen atom (Total: 3 atoms)

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Table Salt (NaCl):

• Elements: Sodium, Chlorine
• Number of Elements: 2
• Atoms: 1 Sodium atom, 1 Chlorine atom (Total: 2 atoms)

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Sulfuric Acid (H₂SO₄):

• Elements: Hydrogen, Sulphur, Oxygen
• Number of Elements: 3
• Atoms: 2 Hydrogen atoms, 1 Sulphur atom, 4 Oxygen atoms (Total: 7 atoms)