Periodicity

• The vertical columns
• The noble gas before the element is used to abbreviate. E.g. Li → 1s22s1 ; Li → [He] 2s1
• Equation for the first ionisation energy of magnesium: Mg (g) → Mg+ (g) + e-
• They are arranged in the order of increasing atomic numbers
• The repeating trends in chemical and physical properties
• The horizontal rows in the periodic table
• Factors that affect ionisation energy

  • Atomic radius
  • Nuclear charge
  • Electron shielding or screening
• Elements change from metals to non-metals
• Factors that affect ionisation energy

  • Atomic radius
  • Nuclear charge
  • Electron shielding or screening
• Dips at S because one 3p orbital contains two electrons, leading to repulsion between paired electrons, hence less energy needed to remove one
• Does first ionisation increase or decrease between the end of one period and the start of the next? Why? Decrease. There is an increase in atomic radius and an increase in electron shielding
• Why does first ionisation energy decrease between group 2 to 3? Decrease between 2 to 3 because in group 3 the outermost electrons are in p orbitals whereas in group 2 they are in s orbital, so the electrons are easier to be removed
• Does first ionisation increase or decrease down a group? Why? Decrease. Shielding increases leading to weaker attraction, atomic radius increases leading to a greater distance between the outer electrons and nucleus, resulting in weaker attraction. The increase in the number of protons is outweighed by the increase in distance
• First Ionisation energy increases across period 3 because of: Increased nuclear charge, Decreased atomic radius, Same electron shielding, which means more energy is needed to remove the first electron
• Dips at Al because the outer electron is in a 3p orbital, higher energy than 3s orbital, so less energy is needed to remove the electron
• Why does first ionisation energy decrease between group 5 to 6? The decrease between 5 to 6 is due to the group 5 electrons in p orbital being single electrons and in group 6 the outermost electrons are spin paired, with some repulsion, making the electrons slightly easier to remove
• Structure, forces, and bonding in every element across period 2:
• Properties of giant metallic lattices:
• Definition of a ductile metal:
• Structure, forces, and bonding in every element across period 3:
• First ionisation decreases down a group
• Reasons for first ionisation decreasing down a group:
• Definition of a malleable metal: