Monday, January 7, 2013

Chapter 5 Study Guide


Chapter 5 Study Guide
Chemical Bonding

Review Notes, Labs, Homework, and the Textbook.

1.    Using the Periodic Table, you should be able to draw the electron dot diagram for all of the elements covered in class.

2.    Ionic Bonds
A.    Know that an ion is a charged atom or group of atoms
B.    A polyatomic ion is what we call a charged group of atoms
C.    Atoms become charged when the gain or lose electrons.
D.   Atoms have positive charges when the lose electrons (mostly metals) and negative charges when they gain electrons (mostly nonmetals).
E.    Ionic Bonds form when electrons are transferred from one atom to another resulting in ions.  The opposite charges of the ions attract each other.  This is a very strong bond.
F.    You should know how to write chemical formulas using ion charges.  You should know how to name compounds using the chemical formula.  I will give you an ion list to use on the test.
G.    You should know the characteristics of ionic compounds:
1)   Ionic compounds form crystals because of the regular repeating pattern of ions.
2)   Conduct electricity when dissolved in water.
3)   High melting points
4)   Not flammable
5)   Almost all ionic compounds (salts) are formed from
a metal and a nonmetal bonding.

3.    Covalent Bonds
A.    Know that covalent bonds form when atoms share electrons.
B.    Usually form when nonmetals bond to other nonmetals.
C.    Sometimes atoms have to share lots of electrons when they bond (example: Nitrogen forms a triple bond).
D.   Covalent molecules often have low melting points and burn easily (more flammable).
E.    Most covalent compounds do not conduct electricity in water like ionic compounds do.
F.    If electrons are not shared equally between all atoms, the molecule is said to be polar.  A polar bond makes one part of the molecule more positive and another part of the molecule more negative.  An example is water where the Hydrogen atoms are more positive and the oxygen is more negative because the electrons like the oxygen better.