HONORS BIO CHEMICAL BONDINGREVIEW

Chemical bond = ______

1) Ionic bond = ______

a. How/why do ions form?

b. What is the “valence” level?

c. How many electrons fill the first three energy levels?

d. How can you tell if an atom will give away or take electrons?

e. An atom which loses an electron has ______charge

  1. An atom which gains an electron has ______charge

Each atom is now a/an “______”

  1. Why do ions bond?

h. Ionic compounds are always what shape? ______

Why? Because the alternating (+) and (-) charges on ions form a very

ordered structure. Ionic compounds are referred to as ______

a.Are ionic bonds strong or weak? ______

b.IN WATER, what happens to an ionic crystal?

c.This is called ______

d.Why does this happen?

e.Ions in water can conduct electricity and are often called

______(ex. Gatorade has them)

2) Covalent bond= two atoms ______a pair of valence electrons

a.Each atom contributes (one/ both/ either) electrons to the pair.

b.Covalent are the (strongest/weakest) kind of chemical bond.

c.Compounds with covalent bonds are called ______

3) How many bonds will an atom form?

Number of bonds = number of electrons needed to fill the

______energy level on an atom

4) How can you tell if a bond will be ionic or covalent?

a) If one atom needs a small number to fill the valence (ex. a nonmetal), and the other has only a few in the valence (ex. a metal), the bond will be ______(ex. NaCl)

b) If both atoms need a small number (ex. 2 nonmetals) to fill their valence, then neither will be willing to give electrons away, and thebond will be ______

(ex. water molecule)

Intermolecular bonds – bonds between molecules

a. Some atoms have a strong ability to attract nearby electrons

- they have high “______”

b. List some elements with high electronegativity ______

c. In covalent compounds, the electrons (will/won’t) be shared equally if one atom has

stronger pull on e- than the other (ex. water molecule)

d.Charged areas on molecules that are close together can be(attracted to/ repelled by) oppositely-chargedareas on nearby molecules

Color intramolecular bonds RED

Color intermolecular bonds BLUE

1)Van der Waals forces – weak attraction between nearby molecules

  1. Slight positive end on one molecule is attracted to slight negative end on a nearby molecule
  2. Very weak bonds, but there are usually lots of them
  3. Temporary bonds, because the electrons keep moving, and charged areas change back and forth
  4. Ex. gecko foot – many tiny fibers, with huge surface area
  5. Molecules on gecko foot touch molecules on wall or glass
  6. Weak but numerous bonds allow gecko to climb walls and ceilings.

CHEMICAL FORMULAS WARMUPName ______

1)Chemical or Molecular Formula

Shows ______

Examples: ______

2)Structural Formula

Shows ______

Examples:

Chemical

Formula: ______

Notice: ______

Formula: ______

Notice: ______

What’s the difference between a formula’s “subscript” and “coefficient”?

______

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