CP BIO Ch. 2.1 CHEMICAL BONDING REVIEW

Chemical bond = ______

1) Ionic bond = ______

a. How do ions form?

b. Atom which lost an electron has ______charge

c. Atom which gain an electron has ______charge

Each atom is now an “_i_____”

e. opposites attract à ______

______

f. ionic compounds are always what shape?

c______or l______

Why? Because alternating (+) and (-) charges

on ions forms a very ordered structure

Ionic compounds are referred to as s______

Ionic bonds are very (strong/weak); but:

a. IN WATER, the crystal ______

b. this is called “d______”)

c. Ions in water can conduct electricity

-are often called “e______”

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 m______

3) How many bonds will an atom form?

Number of bonds = number of electrons needed to have

a full v______level

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

a) If one atom needs a small number (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, the bond will be ______

(ex. water molecule)

Intermolecular bonds – bonds between molecules

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

they have high “e______”

b. 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)

c. Charged areas on molecules that are close together can be attracted to oppositely-charged areas on nearby molecules

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

a. Slight positive end on one molecule is attracted to slight negative end on a nearby molecule

b. Very weak bonds, but there are usually lots of them

c. Temporary bonds, because the electrons keep moving, and charged areas change back and forth

d. Ex. gecko foot – many tiny fibers, with huge surface area

i. Molecules on gecko foot touch molecules on wall or glass

ii. Weak but numerous bonds allow gecko to climb walls and ceilings.

CHEMICAL FORMULAS WARMUP Name ______

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”?

______