L2 The Periodic Table

• Horizontal rows are called periods.
• Vertical columns are called groups.
• Metals are generally on the left side of the periodic table and non-metals are generally on the right side of the periodic table.
• Metalloids which have properties of noth metals and non-metals are found between the metal and non-metals blocks.
• Transition metals are found in the centre of the table. Group VII elements are the halogens or salt-makers. Group VIII elements are the noble or inert gases.
• Trends in the Periodic Table:

  Physical State - Across the period, state changes from solid to liquid to gas. All Group I elements are solids while all Group VIII elements are gases.
• Melting Point - Is the temperature at which the elements change from solid to liquid. It is expressed in degrees Celsius.

  Across the period (left to right): Decreases

  Down the group: Increases
• Boiling Point - Is the temperature of at which the element changes from liquid to gas.

  Across the period (left to right): Decreases

  Down the group: Increases
• Electrical Conductivity - It measures the element's ability to conduct an electric current. It is expressed in ×10⁶/cmΩ
• Electron Arrangement:

  The electrons that are orbiting the nucleus are in electron shells or energy levels. The electron arrangement (configuration) describes the arrangement of electrons in shells or energy levels.
• Valence Electrons:

  The electrons in the outermost shell have the highest energy. They are called the valence electrons.
• Ions:

  An ion is formed when an atom loses or gains electrons in order to become more stable. Ions are charged particles and are found in ionic compounds.
• Bromide: Br¯
• Iodide I¯
• Iron: Fe^(+2) Fe^(+3)
• Copper: Cu^(+) Cu^(+2)
• Zinc: Zn^(+2)
• Lead: Pb^(+2)
• Oxygen: O^(-2)
• Lithium: Li^(+)
• Barium: Ba^(+2)
• Sodium: Na^(+)
• Chloride: Cl^(-)
• Fluoride: F^(-)
• Magnesium: Mg^(+2)
• Calcium: Ca^(+2)
• Potassium: K^(+)
• Aluminium: Al^(+3)
• When an atom loses electrons, it becomes a positive ion, which is called a cation.
• When an atom gains electrons, it becomes a negative ion, which is called an anion.