Unit 5: Chemistry

• Chemical bonding

  Attraction between the two atoms resulting from the simultaneous attraction between their nuclei and other electrons. The energy of the combined atoms is lower than that of the individual atoms resulting in higher stability.
• Covalent bonding -

  ♡ non-metals + non-metals [Intramolecular bonds]

  ♡ orbitals that are half-filled over and electrons are shared.

  ♡ Electronegativity — </= 2,1
• Covalent bonding

  The sharing of electrons between atoms to form s molecule
• Molecule

  Group of two or more atoms that are covalently bonded and that function as a unit
• Ionic bonding -

  ♡ Metals + non-metals

  ♡ Electrons transfer from the metal to non-metal

  ♡ cations and anions attract with strong electrostatic/ coulombic forces.

  ♡ Electtonegativity — >2,1

  ♡ Should have a low first ionization energy to give away an electron

  ♡ Metals give away and become cation

  ♡ Non-metals accept and become anion.

  ♡Form crystal lattice in solid state
• Ionic bonding

  Transfer of electrons between atoms to form cations and anions that attract each other to form a formula unit.
• Metallic bonding-

  ♡ Metals + Metals

  ♡ Atoms are closely packed so the outermost orbitals overlap.

  ♡ Valence electrons are delocalised and move in adjacent orbitals.

  ♡ Positive core ions form a compact crystal lattice

  ♡ Smallest particle — positive core ion
• Metallic bonding

  Forms between positive core ions and delocalised valence electrons in a metal