Ionic and covalent bonds differ in the extent to which a pair of electrons is shared by the atoms that form the bond. Describe what is the primary difference between these two types of bonds?
An ionic bond occurs between atoms when one of the atoms is much better at drawing electrons toward itself than the other. Generally speaking, metals often react with nonmetals to form ionic compounds or salts. A covalent bond occurs when the atoms are approximately equal in their ability to draw electrons toward themselves, which results in a relative equal sharing of the pair of electrons. Again, generally speaking, nonmetals combine with other nonmetals to form covalent compounds.
One theory of acids and bases stipulates that they dissociate into ions when placed in water. What type of ions does an acid and a base produce?
An acid produces H+ ions when in aqueous solution. A base produces OH- ions when in aqueous solution.
Most liquids contract when they freeze. Water however actually expands slightly when moving from its liquid state to a solid frozen state. What accounts for this phenomenon?
This property of water to expand when frozen stems from its molecular structure. In liquid form the water molecules - H2O - are in motion but due to hydrogen bonding are quite close together. However when the temperature is lowered, the molecules slow down and line up in a more rigid configuration that has more open space between the molecules. Once fully frozen it takes up more space then before. This open space actually also makes ice less dense than water, allowing ice to float.