Structure and Bonding

• Atom


  Smallest unit of matter, consists of protons, neutrons, and electrons
• Nucleus


  Center of the atom, contains protons (+) and neutrons (0)
• Electrons (-)


  Orbit around the nucleus in electron shells
• Ionic Bond


  Between metals and non-metals, electrons transferred, forming positive (cation) and negative (anion) ions, Example: Sodium Chloride (NaCl)
• Covalent Bond


  Between non-metals, electrons shared between atoms, Example: Water (H₂O)
• Metallic Bond


  Between metal atoms, delocalized electrons move freely around a lattice of positive ions, Example: Copper (Cu)
• Ionic Compounds


  • High melting and boiling points
  • Conduct electricity when dissolved in water or molten
  • Usually form crystalline solids
• Covalent Compounds


  • Low melting and boiling points
  • Do not conduct electricity
  • Can form simple molecules (e.g., O₂) or large networks (e.g., diamond)
• Metallic Compounds


  • High melting and boiling points
  • Conduct heat and electricity
  • Malleable and ductile
• Electron Shells


  Regions around the nucleus where electrons are found, 1st shell: up to 2 electrons, 2nd shell: up to 8 electrons, 3rd shell: up to 18 electrons
• Valence Electrons


  Electrons in the outermost shell, crucial for bonding
• Check electron configuration to understand bonding behavior