Flammability is the ability of an object to catch fire, or in chemistry terms, the ability to undergo a thermal reaction, for matter in a solid state. Factors that influence matter's flammability include density, heat resistance and available heat. For matter in a gas state, flash point refers to the temperature at which gas ignites. Scientists write flammability as a temperature --- the temperature required to begin a thermal reaction.
Toxicity is the ability of matter to cause damage to other matter. Chemical toxins are inorganic but become toxic when introduced to a living creature's system. Biological toxins, such as viruses and bacteria, are organic and cause infection during contact with a living creature's system. Toxins can be acute, causing damage with a single exposure, or chronic, requiring multiple exposures for contamination.
Oxidation is the reaction of oxygen molecules with organic or inorganic matter. Organic matter, when acted upon by oxygen molecules, plays a role in the aging process and decay. Inorganic matter reacts in different ways to the interaction of oxygen, such as playing a role in the rusting process or working to strengthen other metals, such as aluminum. Oxidation represents the potential for matter to undergo a chemical reaction when in contact with oxygen.
Radioactivity is the rate of travel for energized particles moving through an area in waves. Energizing matter creates this effect, collecting too many electron charges to remain stable. Radioactivity has a degenerative effect on objects, organic and inorganic, located near the source of the radiation. While most forms of radiation are harmless to people, some can cause health problems with extended contact. Radioactivity represents the reaction of matter to ionization.
Light sensitivity is the resulting chemical reaction, which light causes to matter. This chemical change often requires long-term exposure, such as long-term exposure turning paper yellow. Other light frequencies cause effects, such as ultraviolet light exposure creating a chemical reaction in organic creatures, darkening skin and causing burns.