Chemical Bonding Review

Ionic Bonds

  • Definition: An ionic bond involves the transfer of electrons from one atom to another, resulting in the formation of positive and negative ions.
  • Formation: A metallic atom with one electron in its outer energy level may lose that electron to become a cation (positively charged ion). This process makes the atom more stable.
  • Properties:
    • Ionic compounds typically exist as solid crystals.
    • Positive ions formed are smaller than the atoms from which they are derived.
    • Ionic compounds have high melting and boiling points due to the strong electrostatic forces between oppositely charged ions.

Covalent Bonds

  • Definition: A covalent bond is formed when two nonmetallic atoms share electrons.
  • Bonding Electrons: Electrons involved in bonding are called valence electrons.
  • Size of Ions: The size of ions varies across a period in the periodic table; generally, metallic elements decrease in size from left to right.

Key Differences Between Ionic and Covalent Bonds

  • Transfer vs. Sharing: Ionic bonds result from electron transfer resulting in ions, while covalent bonds involve the sharing of electrons between atoms.
  • Nature of Bonds: Ionic bonds typically form between metals and nonmetals, whereas covalent bonds form between nonmetal atoms.

Polyatomic Ions

  • Definition: A polyatomic ion is a group of covalently bonded atoms that collectively carry an overall charge.

Network Solids

  • Definition: A network solid is a chemical compound composed of a continuous network of covalent bonds, with no discrete molecules present. An example would be diamond.

Stability of Atoms

  • Stable Atom: Atoms are more stable when their outer energy level (valence shell) is full. Noble gases have full outer shells, which is why they do not typically form bonds.

Diagramming Bonds

  • Ionic Bonding Model: Create a diagram showing the arrangement of cations and anions in a crystal lattice structure. Label the different parts.
  • Covalent Bonding Model: Draw a model of covalent bonding, showcasing shared electron pairs between atoms and label the components.

Important Concepts

  • Energy Levels: Electrons fill lower energy levels before higher energy levels when forming bonds.
  • Ionic Bonds: Form between elements with opposite charges.
  • Cation Formation: An atom becomes a cation by releasing an electron from its outer shell.