Period 3 and their oxides

• As you go across the period the atomic radius decreases due to the nuclear charge increasing. So there is a greater electrostatic forces of attraction between the nucleus and outer electrons
• Electronegativity increases as nuclear charge increases, atomic radius decreases and shielding stays the same. So there is a greater electrostatic forces of attraction between the nucleus and shared electrons
• Firsts ionisation energy increases as nucleaur charge increases, atomic radius decreases and shielding remains the same. So there is a greater electrostatic forces of attraction so more energy is needed to remove the outer electron
• Amphoteric

  Reacts with both acids and bases
• Lewis acid

  Lone pair acceptor
• Lewis base

  Lone pair doner
• Bronsted-Lowry acid

  Proton donor
• Bronsted-Lowry base

  Proton acceptor
• There is a decrease in 1st ionisation energy between magnesium and aluminium as the outer electron is in a higher energy orbital ( 3p ) in aluminium. Therefore less energy is needed to overcome the electrostatic forces of attraction between the nucleus and outer electron so it is easier to remove
• There is a decrease in 1st ionisation energy between phosphorus and sulfur as in sulfur there is a pair of electrons with repel making it easier to remove
• Why does Na, Mg and Al have a high melting point

  They have a giant metallic structure so lots of energy is required to overcome the strong electrostatic forces of attraction between positive metal ions and negative delocalised electrons. The melting point increases across the period as the metal ions get smaller and more highly charged. There is also more electrons in the electron cloud.
• Why does Si have a high melting point

  It is macromolecular so lots of energy needed to overcome the many strong covalent bonds
• Why does P, S and Cl have low melting points

  They are simple molecular. They have weak intermolecular forces between molecules which require little energy to overcome. Sulphur has the largest Mr so has stronger Van Der Waals between molecules so more energy is required to overcome the forces
• Why does Ar have a low melting point

  It is Monoatomic so it only has weak van Der Waals forces between atoms which require little energy to overcome
• Aluminium oxide is insoluble in water
• Silicon dioxide is insoluble in water
• Sodium hydroxide is highly soluble
• Observations of sodium and water

  Effervescence, colourless solution
• Mg(OH)2 is sparing soluble and slightly alkaline
• Magnesium reacts very slowly with water
• Magnesium reacts vigorously with steam
• Observations of magnesium and steam

  Bright white light and white solid
• Observations of sodium and oxygen

  yellow flame, white powder
• Observations of magnesium and oxygen

  Bright white light and white powder
• Observations of aluminium and oxygen

  White flame, white powder
• Observations of silicon and oxygen

  White flame, white powder
• Observations of phosphorus and oxygen

  Very bright white flame and white powder
• Observations of sulfur and oxygen

  Blue flame, Misty fumes of choking gas
• Sulfur (IV) oxide reacts with water to produce a weakly acidic solution of sulphuric (IV) acid
• Sulfur (VI) oxide reacts vigorously with water producing an acidic solution of sulphuric (VI) acid
• Observations of magnesium and water

  Thick white Precipitate and small bubbles