Chemical Bonding

Atomic bonds form the basis for the myriad of substances that exist, as well as their internal energy, reactions,
and other characteristics. The key types of atomic bonds considered here are metallic, ionic, and covalent.
These are referred to as atomic bonds because they actually bond atoms together. However, sometimes the
term “chemical bonding” is used, but both phrases are referring to the same phenomenon – the various ways
that atoms bond together to form more complex substances. Ionic and covalent bonds are probably the most
crucial in chemistry because they can result in the formation of compounds. Ionic and covalent bonding
between different elements results in the formation of compounds because of the atoms bond together in fixed
ratios, a crucial characteristic of compounds. Metallic bonds result in the formation of alloys as opposed to
compounds because the atoms are not required to combine in fixed ratios.
As physical systems, atoms naturally seek the lowest energy state (the state of existence requiring the least
energy). Accordingly, configurations of small bound groups of atoms, called molecules, are formed. When
individual atoms are sufficiently near each other, their electric charges redistribute in such fashion as to form
attractive electric forces called bonds:

1. covalent – sharing of electrons by two nuclei
2. ionic – electrostatic attraction between oppositely charged ions
3. metallic – attraction of nuclei in crystal for outer shell electrons shared among all available orbitals
4. hydrogen – attraction between H atoms of one molecule and unshared electrons of another
   Instructions
5. Read chapter 9 in Tillery (Keep in mind the summary of equations at the end of the chapter).
6. Answer/solve any two of the following (10 pts. each):
   a. What is the difference between the formation of an ionic bond and formation of a covalent bond?
   b. What relationship, if any, exists between the number of valence electrons and the number of covalent bonds
   that the atom can form? Explain.
   c. What is the difference between a polar covalent bond and a nonpolar covalent bond?
   d. Analyze how you might know for certain that a pure substance you have is an ionic compound and not a
   covalent compound.

Sample Solution