Which statement is correct about an element’s identifying spectrum? The light reflected off an element produces a unique identifying spectrum. The light refracted by an element produces a unique identifying spectrum. The light absorbed by an element produces a unique identifying spectrum. Light emitted by an element produces a unique identifying spectrum.

Light emitted by an element produces a unique identifying spectrum.

Explanation:

When an atom in an element absorbs a photon in the light, an electron in that atom gets excited from the energy of the photon and moves to a higher energy level. When the electron in the ground or lower energy level moves to the excited or higher energy state, it is in an unstable position and so quickly falls back to the lower energy level by emitting a photon with an energy equal to the difference between the two energy levels. The movement of an electron from one energy level to another energy level is known as a transition.  

When an electron in an atom of an element makes a transition from a high energy level to a lower energy level, a spectrum of frequencies of electromagnetic radiation is emitted and this spectrum is known as the emission spectrum of that element. Each atom has so many electron transitions and each transition has a specific energy difference which leads to different radiated wavelengths and forms an emission spectrum. The emission spectrum of each element is unique because the electrons' energy transitions in each element are unique and distinct from one another. Thus, an element can be identified by using its emission spectrum i.e., by examining the colors of light emitted by a particular atom.

heat the gas and measure the pressure