Not necessarily. A substance that is highly combustible has a tendency to ignite easily and burn rapidly, but it may not necessarily be highly reactive. Reactivity refers to how readily a substance undergoes a chemical reaction with other substances, which may or may not lead to combustion.
A highly combustible substance is not necessarily the same as a highly reactive substance, though there can be overlap. Combustibility refers specifically to a material's ability to ignite and burn in the presence of an oxidizer, typically oxygen. In contrast, reactivity encompasses a broader range of chemical interactions, including those that may not involve combustion. Therefore, while many highly combustible substances are also reactive, not all reactive substances are combustible.
Chlorine and fluorine, with fluorine more reactive. Some would also include oxygen. (The two remaining halogens are not gaseous at room temperature.)
Iridium is the least reactive material and also has a very high melting point. It can however react with Aqua Regia sometimes and at very high temperatures it reacts with Oxygen to form Iridium Dioxide. It is the most resistant metal to corrosion, acids and other harmful substances.
Titanium is a highly reactive metal in its pure state, although titanium alloys (which are used as structural elements with a high ratio of strength to weight) are not very reactive. Pure titanium is flammable, and when it burns, it reacts not only with the oxygen in the air, but also with the nitrogen, and it will also react with water (taking the oxygen away from the hydrogen in the water molecule) so titanium fires are almost impossible to extinguish.
JP-8 is both flammable and combustible. It has a flash point of 38°C (100.4°F), making it highly flammable when exposed to a flame or spark, and it can also sustain a fire once ignited. It is important to handle and store JP-8 properly to prevent accidents.
Bromine is corrosive to skin, eyes, and respiratory system upon contact. It is also highly reactive and can ignite in the presence of organic materials, making it both combustible and flammable.
When hydrogen burns, it is combining with oxygen. Once it has combined to form water, the molecule does not want to readily accept more oxygen atoms. Fire is rapid oxidation, so if it is already oxidized, it is done.
Sr - strontium, is a highly reactive alkaline earth. It can react with moisture on the skin and other body parts to produce a very strong alkaline substance which will burn the skin. It is more reactive than calcium metal. It is also classed as a heavy metal.
Chlorine and fluorine, with fluorine more reactive. Some would also include oxygen. (The two remaining halogens are not gaseous at room temperature.)
Carbon is considered highly reactive. This is due to the fact that it can react with many elements on Earth.
Iridium is the least reactive material and also has a very high melting point. It can however react with Aqua Regia sometimes and at very high temperatures it reacts with Oxygen to form Iridium Dioxide. It is the most resistant metal to corrosion, acids and other harmful substances.
Reactivity is the property that describes how readily a substance combines chemically with other substances. Reactivity is also referred to as the rate at which a chemical substance tends to undergo a chemical reaction.
Rubidium is highly reactive, readily reacting with water to release hydrogen gas. It is also reactive with oxygen and halogens, forming various compounds.
Group 17 elements, also known as the halogens (e.g. fluorine, chlorine), are highly reactive due to their tendency to gain one electron to achieve a stable electron configuration. They readily react with other elements to form salts and compounds.
Cadium is more reactive than antium. Cadium, a fictitious element, is known for its highly reactive nature and explosive tendencies. Antium, also fictitious, may have unique properties but is generally considered less reactive compared to cadium.
Sodium Chloride, NaCl, or table salt. The reactive, valency one sodium combines with the also reactive gas chlorine, and they become an ionic compound.
Another term is flammable.