Chemical BondingChemical Bonding

3 Types of Bonding3 Types of Bonding

• Ionic BondingIonic Bonding

• Covalent BondingCovalent Bonding

• Metallic BondingMetallic Bonding

Ionic BondingIonic Bonding

• Ionic bonding is an electrical Ionic bonding is an electrical attraction between two oppositely attraction between two oppositely charged atoms.charged atoms.

• Lose an electron Atom is PositiveLose an electron Atom is Positive

• Gain an electron Atom is NegativeGain an electron Atom is Negative

• Positive Ion is called CationPositive Ion is called Cation

• Negative Ion is called AnionNegative Ion is called Anion

Characteristics of Ionic Characteristics of Ionic CompoundsCompounds

• 1) Crystalline solid at room 1) Crystalline solid at room temperaturetemperature

• 2) Have higher melting and boiling 2) Have higher melting and boiling points compared to covalent bonds.points compared to covalent bonds.

• 3)Conduct electrical current in solution 3)Conduct electrical current in solution state.state.

• 4)Extremely polar bonds.4)Extremely polar bonds.

• 5)Most are soluble in water.5)Most are soluble in water.

Magic #Magic #• The magic number is 8The magic number is 8

• Every atom wants to gain electrons up to 8, or Every atom wants to gain electrons up to 8, or lose electrons to equal zero, In order to be stable lose electrons to equal zero, In order to be stable just like the noble gasesjust like the noble gases

• Exception= Hydrogen= only needs two electronsException= Hydrogen= only needs two electrons

Helpful HintHelpful Hint• An easy way to check if a bond is Ionic:An easy way to check if a bond is Ionic:

• One atom must be from group 1, 2, or 13 One atom must be from group 1, 2, or 13 on the periodic table and the other atom on the periodic table and the other atom from groups 14-17.from groups 14-17.

Oxidation Number (Charge)Oxidation Number (Charge)

GroupGroup 11 22 1313 1414 1515 1616 1717 1818

ChargChargee

+1+1 ++22

+3+3 -4-4 -3-3 -2-2 -1-1 00

Covalent BondsCovalent Bonds

• Covalent Bonds are formed as a Covalent Bonds are formed as a result of the sharing of one or more result of the sharing of one or more pairs of bonding electrons. Each pairs of bonding electrons. Each atom donates half of the electrons to atom donates half of the electrons to be shared.be shared.

2 forms of covalent bonds2 forms of covalent bonds• 1) Polar Covalent - unequal sharing 1) Polar Covalent - unequal sharing

of electronsof electrons

• 2) Non-Polar Covalent – equal sharing 2) Non-Polar Covalent – equal sharing of electrons between atoms. of electrons between atoms.

Single Covalent BondSingle Covalent Bond• A single covalent bond A single covalent bond

would be the sharing of would be the sharing of two electrons between two electrons between the 2 bonded atoms.the 2 bonded atoms.

• H-H H-Cl F-FH-H H-Cl F-F

• The dash line is symbolic The dash line is symbolic of the bonding pair.of the bonding pair.

Double Covalent BondDouble Covalent Bond

• A double covalent bond is 2 pairs of A double covalent bond is 2 pairs of electrons being shared. electrons being shared.

• O=O C=OO=O C=O

Triple Covalent BondTriple Covalent Bond

• A triple covalent bond is the sharing A triple covalent bond is the sharing of 3 pairs of electrons.of 3 pairs of electrons.

• NN==N CN C==C CC C==NN

Metallic BondMetallic Bond

• The metallic bond occurs only The metallic bond occurs only between 2 metal atoms. In this type between 2 metal atoms. In this type of bond the valence electrons are of bond the valence electrons are free to move about the electron free to move about the electron clouds of all metals participating in clouds of all metals participating in the bond. the bond.