States of Matter and Phase Changes

States of Matter

• Matter exists in three forms: solid, liquid, and gas.
• Solids have a fixed shape and volume, with tightly packed particles that vibrate.
• Liquids take the shape of their container but have a fixed volume, with particles moving freely.
• Gases have neither a fixed shape nor volume, with particles moving quickly in all directions.
• Changes of state, like melting (solid to liquid), freezing (liquid to solid), evaporation (liquid to gas), condensation (gas to liquid), and sublimation (solid to gas), occur due to energy transfer.

Phase Changes and Melting Point Graphs

• Melting point graphs show how temperature changes during heating.
• During melting or boiling, the temperature remains constant while energy is used to break bonds.
• This constant temperature is represented by a flat section on the graph.

The Periodic Table

• The periodic table organizes elements by atomic number.
• Elements in the same column (group) have similar properties.
• Elements in the same row (period) show increasing atomic number.
• Metals are on the left, and non-metals are on the right.
• Group 1 (alkali metals) are highly reactive.
• Group 7 (halogens) are reactive non-metals.
• Group 0 (noble gases) are unreactive.

Element Case Study: Oxygen

• Oxygen (O₂) is a non-metal gas essential for respiration and combustion.
• It's found in water (H₂O) and the atmosphere.

Atoms, Elements, and Compounds

• Atoms are the smallest unit of matter.
• Elements are substances made of only one type of atom.
• Compounds form when two or more elements bond chemically.
• Molecules are groups of atoms bonded together.

Chemical Bonding

• Compounds are created through chemical bonding.
• Ionic bonding occurs between metals and non-metals (e.g., NaCl).
• Covalent bonding occurs between non-metals (e.g., H₂O).
• Chemical formulas show the ratio of elements in a compound.

Extracting Elements from Compounds

• Elements can be extracted from compounds using chemical reactions.
• Electrolysis is a method to separate elements (e.g., splitting water).
• Thermal decomposition is another method (e.g., heating copper carbonate).

Mixtures vs. Compounds

• Mixtures contain physically combined substances.
• Compounds contain chemically bonded substances.
• Mixture components retain their properties and are separable by physical methods (e.g., air).
• Compound properties differ significantly from original elements and require chemical reactions to separate.