What is an element? O Substances that can be separtated by physical chemical means.

O Simplest form of matter.

O The smallest unit of an element that maintains the chemial identity of the element.

O Contains more than one kind of particle.

An element is a substance that is made up of the same kind of atoms and

cannot be broken down into simpler substances by any known chemical means

examples of element are iron boron carbon helium calcium hydrogen etc

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.