On the atomic level energy and matter exhibit the characteristics of

Explanation:

The dual behavior of subatomic particles as waves and particles is known as the wave - particle duality.

And this principle is the basis of the quantum theory.

Such principle is widely applied to the electrons; i.e., the electrons posses wave and particle propeties, which must be understodd as that some of their properties may be explained as if they were particles and others as if they were waves.

For example, from the particle point of view electrons have mass. You can find in internet that the mass of one electron is about 9.1093837015×10⁻³¹ kg or about 1/1836 times the mass of one proton.)

Since, the point of view of the wave characteristics, electrons have wavelength, Louis de Broglie deduced the equation that relates the wavelength and the mass, through this realtion:

         λ = h / mv

it should be p1 v1 = p2 v2