Types of Bonds, Bond energy, and Lewis Structure

Covalent vs Ionic Bonds
Covalent Bonds

• result of the sharing of electons by two nonmetals
• both atoms involved in the bond share electrons to fill their particular octet

Ionic Bonds

• involves the giving and reciving of electrons between a cation and an anion
• oppositely charged ions then attract to each other forming a bond

Octet Rule

• Atoms cannot have more than 8 electrons 
• A full 8 electron shell is considered stable
• Some atoms don't need 8 electrons

Exceptions to the rule:

• hydrogen and helium only requires 2 electrons
• boron only requires 6 electrons to be stable, but it will form 4 bonds when necessary
• beryllium will have fewer than 8 as well, it likes 4 electrons in its valence
• elements in period 3 and beyond can have expanded octets because the d sublevel becomes available (ex. sulfur, phosphorus, xenon, krypton)

Lewis Strucutre for Atoms

• figure out how many valence electrons are needed for the atom
• write the atom's symbol in the center
• place electrons singularly on each side before doubling up the electrons until all valence electrons are placed
• EX: Nitrogen has 5 valence electrons which are placed in the Lewis structure below
  

Bond Length and Energy

• Single bonds: longest and weakest bonds
• Double bonds: shorter and stronger than single bonds
• Triple bonds: shortest and strongest bonds

• read from right to left
• the lowest point on the graph is high energy and where the bond forms
• 0 energy is when the two atoms are isolated from each other
• energy being absorbed is the same amount of energy being released