Periodicity

• How are the elements arranged in a periodic table?

  In order of increasing atomic numbers
• What is a period on a periodic table?

  The horizontal rows in the periodic table
• What is a group on a periodic table?

  The vertical columns
• What is meant by periodicity?

  The repeating trends in chemical and physical properties
• What change happens across each period?

  Elements change from metals to non-metals
• How can the electron configuration be written in short?

  The noble gas before the element is used to abbreviate
• Write the short form of the electron configuration for lithium.

  Li → [He] 2s1
• Define first ionisation energy.

  The energy required to remove one electron
• Write an equation for the first ionisation energy of magnesium.

  Mg (g) → Mg+ (g) + e-
• What are the factors that affect ionisation energy?

  Atomic radius, nuclear charge, electron shielding
• Explain the trend of first ionisation energy across period 3.

  • Increases due to increased nuclear charge
  • Decreased atomic radius
  • Same electron shielding
  • Dips at Al due to higher energy 3p orbital
  • Dips at S due to electron repulsion in paired 3p orbital
• Why does first ionisation energy decrease between group 2 to 3?

  Electrons in group 3 are easier to remove
• Why does first ionisation energy decrease between group 5 to 6?

  Group 6 has paired electrons causing repulsion
• Does first ionisation energy increase or decrease between the end of one period and the start of the next? Why?

  Decrease due to increased atomic radius and shielding
• Does first ionisation energy increase or decrease down a group? Why?

  Decrease due to increased shielding and atomic radius
• What are the properties of giant metallic lattices?

  • High melting and boiling point
  • Good electrical conductors
  • Malleability
  • Ductility
• What is a ductile metal?

  The metal can be made into wires
• What does malleable metal mean?

  The metal can be shaped into different forms
• Describe the structure, forces, and bonding in every element across period 2.

  • Li & Be: Giant metallic; strong attraction; metallic bonding
  • B & C: Giant covalent; strong forces; covalent bonding
  • N2, O2, F2, Ne: Simple molecular; weak intermolecular forces; covalent bonding
• Describe the structure, forces, and bonding in every element across period 3.

  • Na, Mg, Al: Giant metallic; strong attraction; metallic bonding
  • Si: Giant covalent; strong forces; covalent bonding
  • P4, S8, Cl2, Ar: Simple molecular; weak intermolecular forces; covalent bonding