Molecules are held together by either covalent bonding or ionic bonding. Several types of non-metal elements exist only as molecules in the environment. For example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements.
In general, chiropractic services range from approximately $30 to $200 per session. Of course, each type of treatment has a different cost. For example, an initial consultation with a chiropractor may be provided at no charge, while a typical therapy session costs about $65 on average.
The Bureau of Labor Statistics (BLS) maintains a database of employment information, which includes chiropractors. According to the BLS, chiropractors reported an average income of $78,780 in 2010. However, there was a significant variance between the lowest and highest earners. The lower 10 percent of earners averaged $14.96 per hour, or $31,120 per year, while the highest 10 percent reported average income of $68.55 per hour, or $142,570, per year.