They're elements. Elements are the simplest form of any substance that cannot be broken down by any chemical methods, including electrolysis or even heat. Examples include oxygen, hydrogen etc.
An atom is the simplest particle that exists and retains the property of the element. A compound is made up of two or more elements chemically combined.
Gravitational force -an attractive force that exists between all objects with mass; an object with mass attracts another object with mass; the magnitude of the force is directly proportional to the masses of the two objects and inversely proportional to the square of the distance between the two objects.
The kind of energy released when atoms are rearranged to form new bonds is called Chemical energy.
