s-block

• 1. Block Elements

  Alkali Metals & Alkaline Earth Metals except Helium (Noble Gas)
• The S-Orbital

  • Contains two electrons
  • The energy levels increase as you move further from the nucleus
  • The order of size is 1s < 2s < 3s and so on
  • As the energy level increases, the electrons are located further from the nucleus, so the orbitals get bigger
• Electron Configuration

  • Hydrogen: 1s1
  • Helium: 1s2
  • Lithium: [He]2s1
  • Beryllium: [He]2s2
  • Sodium: [Ne]3s1
  • Magnesium: [Ne]3s2
  • Potassium: [Ar]4s1
  • Calcium: [Ar]4s2
  • Rubidium: [Kr]5s1
  • Strontium: [Kr]5s2
  • Caesium: [Xe]6s1
  • Barium: [Xe]6s2
  • Francium: [Rn]7s1
  • Radium: [Rn]7s2
• Electron Configuration

  • The first column of the s-block elements begins with Hydrogen, which ends on subshell S of shell 1 with one electron
  • The first column of s-block elements counts from shell 1 (Hydrogen) to shell 7 (Francium), increasing by 1 shell when counting downwards
  • The first column always ends with having 1 electron in the s subshell
  • The second column of the s-block elements begins with Helium, which ends on subshell S of shell 1 with two electrons
  • The second column of s-block elements also counts from shell 1 (Helium) to shell 7 (Radium)
  • The second column always ends with having 2 electrons in the s subshell
• Characteristic Properties of S-Block Elements

  • Highly reactive
  • Excellent conductors of heat and electricity
  • Soft
  • Have low boiling and melting points
• There are 14 s-block elements