Sodium by itself - pretty bad
Chlorine by itself - pretty bad

sodium cloride by itself - not bad at all (until your doctor tells you to cut back on it).

On a more serious note (oops, forgot where we are.....), a good book to have around and to help the curious is Why is there antifreeze in my toothpaste: [amazon.com]

Better living through chemistry!!

Beware DHMO! [dhmo.org]

Each year, Dihydrogen Monoxide is a known causative component in many thousands of deaths and is a major contributor to millions upon millions of dollars in damage to property and the environment. Some of the known perils of Dihydrogen Monoxide are:

Death due to accidental inhalation of DHMO, even in small quantities.
Prolonged exposure to solid DHMO causes severe tissue damage.
Excessive ingestion produces a number of unpleasant though not typically life-threatening side-effects.
DHMO is a major component of acid rain.
Gaseous DHMO can cause severe burns.
Contributes to soil erosion.
Leads to corrosion and oxidation of many metals.
Contamination of electrical systems often causes short-circuits.
Exposure decreases effectiveness of automobile brakes.
Found in biopsies of pre-cancerous tumors and lesions.

Yep, too many people who don't understand basic facts...