Iconic and covalent bonds

Question

1) How are ionic bonds and covalent bonds different?

2) Describe the relationship between the length of a bond and the strength of that bond.

3) Identify the type(s) of bond(s) found in the following molecules:

a. CCl4 ___________________________

b. Li2O ___________________________

c. NF3 ___________________________

d. CaSO4 ___________________________

e. SO2 ___________________________

f. Mg(OH)2 ___________________________

4) Define electronegativity.

5) Use electronegativity values to place the following elements in increasing order: F, N, H, P, Si,

C, O

6) Determine if the bond between atoms in each example below is nonpolar covalent, polar

covalent, or ionic.

a. H-H __________________

b. P-Cl __________________

c. F-F __________________

d. Na-Br __________________

e. N-F __________________

f. Mg-O __________________

g. C-H __________________

h. H-Cl __________________

Answer 1

1. Ionic bonds are the result of valence electrons being donated from one atom to another, thus creating a positively charge ion and a negatively charged ion. Since opposite charges attract one another, the attractive forces between the positive ion and negative ion hold the two atoms together in a bond. In contrast, covalent bonds are formed when valence electrons are shared between two atoms, usually to allow both of the atoms to have a full octet (i.e. 8 valence electrons).
2. The relationship between the length of a bond and the strength of that bond is inversely proportional. That is, as the length of the bond increases, the strength of bond decreases, and vice versa.
3. a. polar covalent, b. ionic, c. polar covalent, d. ionic and polar covalent, e. polar, f. ionic and polar covalent
4. Electronegativity is the tendency for an atom to attract electrons within its bonds to other atoms. Simply put, it can be thought of as the degree to which an atom "likes" electrons.
5. The periodic table trend for electronegativity, in general, increases as you move from left to right across a given row and as you go up a given column. Order: P, H, C, S, N, O, F
6. a. non polar covalent, b. polar covalent, c. non polar covalent, d. ionic, e. polar covalent, f. ionic, g. nonpolar covalent, h. polar covalent