The different isotopes of an element are identified by writing the mass number of the atom in the upper left corner of the symbol for the element. If the atoms are neutral, they also must contain six electrons. The only difference between these isotopes is the number of neutrons in the nucleus. 1 Electromagnetic Radiation Much of what is known about the structure of the electrons in an atom has been obtained by studying the interaction between matter and different forms of electromagnetic radiation . Electromagnetic radiation has some of the properties of both a particle and a wave.
Particles have a definite mass and they occupy space.
Waves have no mass and yet they carry energy as they travel through space. The idealized drawing of a wave in the figure below illustrates the definitions of amplitude and wavelength. Click here to check your answer to Practice Problem 3 Click here to see a solution to Practice Problem 3 Light and Other Forms of Electromagnetic Radiation Light is a wave with both electric and magnetic components. It is therefore a form of electromagnetic radiation . Visible light contains the narrow band of frequencies and wavelengths in the portion of the electro-magnetic spectrum that our eyes can detect.