Why does emission spectrum occur

The archer releases the arrow and the potential energy is translated into kinetic energy as the arrow moves. It turns out that electrons behave the same way when energy is put into the system or released from the system. The electrons in an atom tend to be arranged in such a way that the energy of the atom is as low as possible.

The ground state of an atom is the lowest energy state of the atom. When those atoms are given energy, the electrons absorb the energy and move to a higher energy level. These energy levels of the electrons in atoms are quantized, meaning again that the electron must move from one energy level to another in discrete steps, rather than continuously. An excited state of an atom is a state where its potential energy is higher than the ground state. An atom in the excited state is not stable.

When it returns back to the ground state, it releases the energy that it had previously gained in the form of electromagnetic radiation. So how do atoms gain energy in the first place? One way is to pass an electric current through an enclosed sample of a gas at low pressure. Since the electron energy levels are unique for each element, every gas discharge tube will glow with a distinctive color, depending on the identity of the gas see below.

However, only signs that glow with the red-orange color seen in the figure are actually filled with neon. Signs of other colors contain different gases or mixtures of gases.

Scientists studied the distinctive pink color of the gas discharge created by hydrogen gas. An atomic emission spectrum is the pattern of lines formed when light passes through a prism to separate it into the different frequencies of light it contains.

Emission spectrum Discrete, non-continuous spectra are an observable result of the physics of atoms. Unlike a continuous spectrum source, which can radiate at an arbitrary frequency just change the effective temperature , the electron clouds surrounding the nuclei of atoms have very specific energies dictated by quantum mechanics.

Each element on the periodic table has its own set of possible energy levels. Electrons tend to settle to the ground state, so an excited atom with an electron in a higher energy level will emit a wave of light with that exact energy to allow the electron to fall into the ground state.

This energy corresponds to a specific color, or wavelength, of light, so we see a bright line at that exact wavelength. We can observe emission lines in spectra from comets, nebula and certain types of stars.