The s-block of the periodic table of elements consists of the first two groups: the alkali metals and alkaline earth metals, plus hydrogen. These elements are distinguished by the property that in the atomic ground state, the highest-energy electron is in an s-orbital. Elements of the s-block are strong reductants.

Related topics

• Periodic table block
  • p-block
  • d-block
  • f-block
  • g-block
• Electron configuration