Light is one of the most prominent topics in Physics. Several studies explained various things about the light, how it travels, how it reflects etc., and many more. One of the other important concepts is the spectral series. Let us understand the spectral series and spectral series of hydrogen atoms.
The spectral series is in the form of lines. Whenever the atoms of an element get excited and emit the light rays from higher energy levels to lower energy levels, these can be calculated using the Rydberg formula.
Spectral Series of Hydrogen Atoms
Studying the hydrogen atom is the easiest way of understanding the principle of spectral series. It is the simplest atom that we can get to observe the spectral series. To observe these series of the spectrum, we need to send a beam of light into the slit. Every component of this beam of light may form a different image which can appear as some spectral series when the images are exposed to a spectroscope.
These spectral series are like parallel lines with uniform distance and speed. The wavelength of light can influence these spacings if the wavelength of spectral lines is higher and the spacing is more, and the lines are visible like they are apart from each other. On the other hand, if the wavelength is less, the lines also come closer and seem to be beside each other. If the shortest wavelength is recorded, then the distance between the lines was also recorded. This is called the series limit. By observing this series limit, we can say whether the volume is high or low.
We can observe the spectral lines or series from the spectroscope in a hydrogen atom known as Hydrogen Spectrum Series. The Spectrum series can be observed in several different ways at different stages of the hydrogen atom spectrum. So we have different classifications in the hydrogen Spectrum series. They are -
Rydberg Formula
As we know that the hydrogen spectrum is an emission spectrum, the atoms get excited and transition to different energy levels. Niels Bohr can study these transitions. Again he gave a formula known as the Rydberg formula to calculate the wavelength of these spectral lines.
1/λ = RZ2(1/n12− 1/n2h).
Where,
Z is the atomic number
NL is the lower energy level
NH is the higher energy level
𝜆 is the wavelength
R is the Rydberg constant has the value 1.09737✕107 m⁻¹
Lyman Series
The Lyman Series can be stated as an advance or enhancement of Bohr's model. It was discovered during the 19th century by a scientist called alignment. It was named after him. According to Lyman, the atom transitions can take place from higher energy levels to energy level 1. That is n1 equal to 1. We can understand by observing the values of different wavelengths at each energy level.
Balmer Series (n1=2)
The series of spectral lines can be discovered by a scientist Balmer in the year 1882. It is also similar to that of the Lyman series. But the variation occurs in the level of energy. The lineman observes spectral series at energy level 1 whereas the Balmer observed spectral series at energy level 2. That means the transitions of atoms occur from higher energy levels to the second energy level.
Paschen Series
German physicist Friedrich Paschen discovers this series of spectrum lines in the hydrogen Spectrum series in the year 1902. All these series were named after the scientist. This series also explains spectral lines' nature when the transitions took place from higher energy levels to the third energy level.
From this level of series, all the subsequent levels may overlap with this series.
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Brackett Series
This series of spectral lines can be observed in the year 1922 Friedrich Sumner Brackett. When electrons transition from higher energy levels to the 4th energy level, the Spectrum series is called the Brackett Series.
Pfund Series
The series, which August Harman Pfund observed in 1924, is known as beef and cereals named after him. He observed that the series of spectral lines might appear when electrons' transitions take place from higher energy levels to the fifth energy level.
Humphreys Series
American Physicist Curtis J Humphreys, in 1953, has displayed a spectrum of series where the electron transition takes place from higher energy states to 6th energy states.
Still, several series are discovered, but they are unnamed. As the research and studies are increasing, several inventions and discoveries can come to the spotlight.
FAQs on Spectral Series
1. What is a spectral series in Physics?
A spectral series is a specific set of lines in the light spectrum of an element. These lines are created when electrons jump between different quantized energy levels within an atom. Each series is defined by the specific lower energy level that the electrons transition to from various higher levels.
2. What are the main types of spectral lines?
There are two primary types of spectral lines that help us understand the interaction of light and matter:
- Emission lines: These appear as bright lines on a dark background. They are formed when an excited electron falls to a lower energy state, releasing a photon of a specific wavelength.
- Absorption lines: These are dark lines that appear on a continuous spectrum. They are formed when an atom absorbs a photon of a specific wavelength, causing an electron to jump to a higher energy state.
3. Can you list the major spectral series for the hydrogen atom?
Yes, the main spectral series for the hydrogen atom are named after the scientists who discovered them. They include:
- Lyman Series: Occurs in the Ultraviolet (UV) region.
- Balmer Series: The only series in the Visible light region.
- Paschen Series: Occurs in the Infrared (IR) region.
- Brackett Series: Also found in the Infrared (IR) region.
- Pfund Series: Found in the far-Infrared (IR) region.
4. Which spectral series of hydrogen is visible to the human eye?
The Balmer series is the only spectral series of the hydrogen atom that falls within the visible portion of the electromagnetic spectrum. This is why its lines, such as the prominent red H-alpha line, were the first to be observed and studied by scientists.
5. Why do spectral lines only appear at specific wavelengths and not as a continuous rainbow?
Spectral lines appear at specific wavelengths because electron energy levels within an atom are quantized, meaning electrons can only exist in fixed, discrete orbits, not in between. An electron must absorb or release an exact amount of energy to jump between these levels. This exact energy corresponds to a photon of a specific wavelength, resulting in sharp lines rather than a continuous spectrum.
6. What is the Rydberg formula and what is its main purpose?
The Rydberg formula is a crucial mathematical equation in atomic physics. Its main purpose is to accurately predict the wavelength of the light emitted or absorbed when an electron moves between two specific energy levels in a hydrogen atom. It provides strong mathematical proof for the quantized model of the atom.
7. How do scientists use the concept of spectral series to identify what distant stars are made of?
Every element has a unique set of electron energy levels, which produces a unique pattern of spectral lines, like a 'fingerprint'. Scientists use an instrument called a spectroscope to analyse the light from a star. By matching the pattern of dark absorption lines in the starlight to the known spectral fingerprints of elements, they can determine the chemical composition of the star's atmosphere.
