* Chemical Bonding: When elements form compounds, they undergo chemical reactions, breaking old bonds and forming new ones. This creates a completely new substance with its own distinct structure.
* New Properties: The properties of a compound are determined by the arrangement and interaction of its atoms, not just the individual elements. This leads to entirely different physical properties like:
* Melting point: Water (H₂O) melts at 0°C, while hydrogen (H₂) is a gas at room temperature and oxygen (O₂) is also a gas.
* Boiling point: Sodium chloride (NaCl) has a high melting and boiling point, whereas sodium (Na) is a soft metal and chlorine (Cl₂) is a gas.
* Density: Ethanol (C₂H₅OH) is a liquid, while carbon (C) is a solid and hydrogen (H₂) and oxygen (O₂) are gases.
* Color: Copper sulfate (CuSO₄) is blue, while copper (Cu) is reddish-brown and sulfur (S) is yellow.
In summary: While compounds are made from elements, the chemical bonds and arrangement of atoms create new and unique physical properties, distinct from the original elements.
