Chemical Bonding

• Noble gases have electron

  configurations that prevent them from

  forming compound with other elements
• Noble gases have filled valence shells

  with valence electron configuration of

  ns2 np6
• Valence electrons are involved in bonding
• In ionic bonding, electrons are loss or

  gained forming cations and anions.
• In covalent bonding, electrons are shared.
• Whether electrons are transferred or

  shared, the goal is to be stable (having 8

  electrons in the outermost shell or an octet)
• VALENCE ELECTRON- Outermost electrons of

  atoms; often involved in bonding.
• LEWIS DOT STRUCTURE- consists of the

  symbol of an element and one dot for each

  valence electron in an atom of the element.
• Chemical Bonding- refers to the attractive

  forces that hold atoms together in

  compounds
• ionic bond - most often occurs between a metal and a nonmetal
• Oxidation number- number of electrons gained

  or loss
• ION - an atom or a group of atoms that carries an

  electrical charge. It is produced when an atom

  gained of loss an electron/ electrons.
• Anion - A negatively charged ion that has more

  electrons than protons
• Cation- a positively charged ion that has fewer

  electrons than protons
• When an element combines with another element by gaining or losing

  electrons, then its valency is called electrovalency.
• The compound formed is an electrovalent or ionic compound
• The elements that lose electrons form a positive ion and have positive

  electrovalency.
• The elements that gain electrons form a negative ion and have negative

  electrovalency.
• Covalent Bond- a bond in which two electrons are

  shared by two atoms.
• Covalent compounds- are compounds that contain

  covalent bonds.
• lone pairs- pairs of valence electrons that are not

  involved in covalent bond formation.
• Lewis structure is a representation of covalent bonding

  in which shared electron pairs are shown either as lines

  or as pairs of dots between two atoms, and lone pairs

  are shown as pairs of dots on individual atoms.
• Covalency occurs when an element shares electrons with other atoms of the same or different elements to produce a stable electrical state.
• The maximum number of bonds formed by an atom to reach the stable electronic configuration is also known as covalency
• NONPOLAR MOLECULES - electron pair is

  shared equally between the atom.
• POLAR MOLECULES occur when two atoms do not share electrons equally in a covalent bond
• Resonance can be considered as the

  condition occurring when more than one valid Lewis structure can be written for a particular molecule.