Question

How can atomic spectra be used to identify elements?

Answer 1

Hint: Atomic emission spectra represent the electrons in an atom returning lower energy levels. Due to the nature of quantum physics electrons can absorb and emit only specific discrete quantum physics, electrons can absorb and emit only specific discrete energies. Every element has a characteristic arrangement of electron orbitals.

Complete answer:
Atomic spectroscopy is the study of the electromagnetic radiation absorbed and emitted by atoms. Since unique elements have characteristic spectra, atomic spectroscopy, specifically the electromagnetic spectrum or mass spectrum, is applied for determination of elemental compositions. Because each element has a different number of protons in the nucleus, the energy level of each element is unique. In emission spectra, bright lines will show up corresponding to the difference between energy levels of the elements where in an absorption spectrum, the lines will be dark since every element has unique energy levels, the spectra can help identify elements in a sample.

Additional Information:
Electrons exist in energy levels within an atom; atomic orbitals are quantized, meaning they exist as defined values instead being continuous. Electrons may move between orbitals, but in doing so they must absorb or emit energy equal to the energy difference of their atoms specific quantized orbital energy levels. In optical spectroscopy, energy absorbed to move an electron to a higher energy level or the energy emitted as the electron moves to a slower energy level is absorbed or emitted in the form of photons. Because each element has a unique number of electrons, an atom will release energy in a pattern unique to its elemental identity and thus will absorb photons in a correspondingly unique pattern.
The relationship between the concentration of atoms, the distance the light travels through the collection of atoms, and the portion of the light absorbed is given by the Beer-Lambert Law.
Atomic mass spectrometry is similar to the other types of mass spectrometry in that it consists of an ion source, a mass analyzer and detector. Atoms' identities are determined by their mass to charge ratio and their concentration are determined by the number of ions detected. In optical spectroscopy if the wavelength of the source light has energy corresponding to the energy difference between two energy levels of the atoms, a portion of the light will be absorbed. The difference between the intensity of emitted light from source and the absorbed by detection gives absorbance values. This absorbance value can be used to determine the concentration of a given element within the sample.

Note: Optical spectroscopy is often less expensive and has performance adequate for many tasks, it is far more common. Atomic absorption devices the type of atoms present in a sample, or amount of atoms present in a sample can be deduced from measuring these changes in light wavelength and light intensity. Atomic ion sources are generally modifications of atomic optical spectroscopy from atom sources. For all atomic spectroscopy a sample must be atomized and vapourised with the exception of flames and graphite furnaces, which are most commonly used for atomic absorption spectroscopy most sources are used for atomic emission spectroscopy.