Name: line spectra from heated gases
Uploaded: 2020-09-03T13:38:27.000Z
Duration: 2 min 39 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Physical Science

Matter and its Interactions

PS.PSc.1.4

Emission Spectra

원자가 에너지를 흡수하면 전자는 들뜬 상태가 되어 더 높은 에너지 준위로 이동합니다. 전자가 낮은 에너지 상태나 바닥 상태로 이완되면 과잉 에너지는 광자로 방출됩니다. 흡수되고 방출되는 빛의 파장은 에너지의 높고 낮은 수준의 차이에 따라 달라집니다.

높은 에너지로 방출된 빛은 높은 에너지 준위로부터 이완된 전자에 기인하고, 낮은 에너지로 방출된 빛은 낮은 에너지 준위에서 이완된 전자에 기인합니다. 방출 스펙트럼은 다양한 파장에서 방출된 방사선의 척도입니다. 순수한 원소의 경우, 방출 스펙트럼을 보면 넓은 스펙트럼이 아닌 특정한 파장의 선으로 나타납니다.

이것이 수소의 방출 스펙트럼입니다. 가시광선 영역에 있는 스펙트럼 선 계열을 발머 계열이라고 합니다. 전자가 n 3보다 높은 에너지 준웨에서 n 2로 전이될 때 발생합니다.

가시광선 스펙트럼은 410, 434, 486, 656 나노미터에서 스펙트럼 라인으로 나타나며, 이는 각각 n=3, 4, 5, 6에서 n 2로 에너지 준위가 전환된 것입니다. 추가 스펙트럼 라인은 UV 영역의 라이먼 계열과 적외선 영역의 파셴 계열과 같이 가시 범위 밖에서 측정할 수 있습니다. 수소에 대한 스펙트럼 라인의 파장은 수학적 표현을 사용하여 예측할 수 있으며, 여기서 R-H는 리드베르크 상수, n1은 낮은 에너지 준위의 주 양자수, n2는 높은 에너지 준위의 주 양자수입니다.

발머 계열의 경우 n1 은 2입니다 원자마다 에너지 준위가 다르기 때문에 스펙트럼 방출 라인은 원소마다 다르며 물질을 식별하는 데 사용됩니다. 방출 스펙트럼의 역은 흡수 스펙트럼입니다. 수소를 보면 흡수 스펙트럼 라인은 방출 스펙트럼과 같은 파장에 위치하지만 어둡습니다.

이것들은 연속적인 백색광 스펙트럼에 노출되었을 때 수소 원자에 의해 흡수되는 빛의 파장입니다.

방출 스펙트럼

고체, 액체 또는 응축된 기체가 충분히 가열되면 초과 에너지 중 일부를 빛으로 방출합니다. 이러한 방식으로 생성된 광자는 다양한 에너지를 가지며, 그에 따라 깨지지 않는 일련의 파장이 존재하는 연속 스펙트럼을 생성합니다.

연속 스펙트럼과 달리 빛은 스펙트럼 영역 전체에 산재된 매우 좁은 선폭을 갖는 이산 또는 선 스펙트럼으로 나타날 수도 있습니다. 전류를 사용하여 낮은 부분압에서 가스를 여기시키거나 가열하면 선 스펙트럼이 생성됩니다. 형광등이나 네온사인도 이런 식으로 작동합니다. 각 요소는 분자와 마찬가지로 고유한 특징적인 선 세트를 표시하지만 스펙트럼은 일반적으로 훨씬 더 복잡합니다.

각 방출선은 단일 파장의 빛으로 구성됩니다. 이는 가스에서 방출되는 빛이 일련의 개별 에너지로 구성됨을 의미합니다. 예를 들어, 낮은 압력에서 수소 가스가 들어 있는 관을 방전이 통과하면 H_2 분자가 별도의 H 원자로 분해되어 파란색-분홍색이 관찰됩니다. 빛을 프리즘에 통과시키면 선 스펙트럼이 생성되는데, 이는 이 빛이 가시광선 파장 4개의 광자로 구성되어 있음을 나타냅니다.

원자와 분자의 개별 스펙트럼의 기원은 19세기 후반 과학자들에게 극도로 수수께끼였습니다. 고전 전자기 이론에 따르면 연속 스펙트럼만 관찰해야 합니다. 수소 원자에 대한 다른 개별 선은 UV 및 IR 영역에서 발견되었습니다. Johannes Rydberg는 Balmer의 작업을 일반화하고 n_1과 n_2가 정수이고 n_1 < n_2인 가시 범위에 국한된 방출선뿐만 아니라 모든 수소 방출선을 예측하는 경험적 공식을 개발했습니다.

<img alt="Eq1" src="https://www.jove.com/files/core/CDNSource/lessons/977/977_Equations-01.png" style="height: 40px;" />

19세기 후반에도 분광학은 매우 정밀한 과학이어서 수소의 파장은 매우 높은 정확도로 측정되었으며, 이는 리드베리 상수도 매우 정확하게 결정될 수 있음을 의미했습니다. 리드베리 공식과 같은 간단한 공식이 그토록 정확한 측정을 설명할 수 있다는 사실은 그 당시에는 놀랍게 보였습니다. 하지만 1913년 닐스 보어가 방출 스펙트럼을 설명함으로써 과학자들은 결국 고전 물리학을 버리고 현대 양자역학의 발전을 촉진하는 결정적인 전환기를 맞이했습니다.

이 문서는 에서 발췌되었습니다 <a href="https://openstax.org/books/chemistry-atoms-first-2e/pages/3-1-electromagnetic-energy">Openstax, Chemistry 2e, Section 3.1: Electromagnetic Energy</a>.

고체, 액체 또는 응축 가스가 충분히 가열되면 초과 에너지의 일부를 빛으로 방출합니다. 이러한 방식으로 생성 된 광자는 ...

Education

교육

JoVE Core

Chemistry

화학

하나

Electronic Structure of Atoms

원자의 전자 구조

KEY TERMS AND CONCEPTS

주요 용어 및 개념

line spectra from heated gases

Line spectra are produced when heated gases give off light at specific wavelengths. In contrast, hot solids, liquids, or condensed gases radiate excess energy as a continuous spectrum. That spectrum contains an unbroken range of wavelengths.

A gas at low partial pressure can produce a line spectrum when it is excited by an electric current or heated. Fluorescent light bulbs and neon signs work in this way. Each element has its own characteristic set of lines, and molecules can also produce line spectra, although their patterns are usually more complex.

Each emission line is a single wavelength of light. That means the light from a gas is made of discrete energies rather than a smooth spread of values. A good example is hydrogen gas in an electric discharge tube. The H2 molecules break apart into separate H atoms, and the gas gives off a blue-pink color.

When that light is passed through a prism, it separates into a line spectrum. For hydrogen, this shows four visible wavelengths. Scientists also found other hydrogen lines in the ultraviolet and infrared regions. In the late nineteenth century, these discrete spectra were hard to explain because classical electromagnetic theory predicted only continuous spectra.

Johannes Rydberg extended Balmer's work and wrote an empirical formula that predicted all of hydrogen's emission lines, not just the visible ones. The wavelengths of hydrogen were measured with high accuracy, so the Rydberg constant could also be determined very precisely. Later, Niels Bohr explained emission spectra in 1913. His explanation helped push scientists away from classical physics and toward modern quantum mechanics.

Line Spectra from Heated Gases

the wave nature of light

Measuring Light with Wavelength and Frequency

Light can be described as an electromagnetic wave, and its behavior helps explain many patterns seen in science. For centuries, scientists have tried to understand light. Newton used lenses and prisms to show that white light is made of the colors of the rainbow mixed together. He explained light as tiny particles moving at high speed. Other scientists, including Christiaan Huygens, showed that reflection and refraction could also be explained by treating light as a wave. At the time, people...

the electromagnetic spectrum

Electromagnetic Waves: Uses Across the Spectrum

The electromagnetic spectrum includes all electromagnetic radiation arranged by frequency and wavelength. Visible light is only a small part of it, and each color of visible light has its own frequency and wavelength. Different parts of the spectrum also use different units. Radio waves are usually measured in MHz, while the visible range is often measured in nm or angstroms. The spectrum is organized from radio waves to gamma rays as frequency increases and wavelength decreases. Radio waves...

interference and diffraction

Wave Patterns from Light and Slits

Light can form wave patterns through interference and diffraction. When two electromagnetic waves meet with their peaks and troughs lined up, they combine into a larger wave. This is constructive interference, and the waves are in phase. When a peak of one wave meets a trough of the other, the waves reduce each other. This is destructive interference, and the result has a much lower amplitude. Diffraction is another wave behavior. When light passes through a slit that is about the same size as...

photoelectric effect

Why Light Ejects Electrons from Metals

Light can eject electrons from a metal surface when it has the right frequency. This process is called the photoelectric effect. Each metal has its own threshold frequency, which is the minimum light frequency needed to free electrons. Light below the threshold frequency cannot cause emission, even if it is very bright. When the light frequency is above the threshold, electrons are ejected. In that case, the number of electrons released is directly proportional to the intensity, or brightness,...

the bohr model

Bohr’s Quantized Atomic Orbits

Bohr’s quantized atomic orbits explain why hydrogen atoms can stay stable. Early in the twentieth century, Ernest Rutherford and his colleagues described atoms as tiny dense nuclei with lighter electrons moving around them. This picture was called the planetary model because it compared the atom to a miniature solar system, with electrons orbiting the nucleus like planets around the sun. The simplest atom is hydrogen. It has one proton in the nucleus and one electron moving around it. In the...

emission spectra

Line spectra are produced when heated gases give off light at specific wavelengths. In contrast, hot solids, liquids, or condensed gases radiate excess energy as a continuous spectrum. That spectrum contains an unbroken range of wavelengths. A gas at low partial pressure can produce a line spectrum when it is excited by an electric current or heated. Fluorescent light bulbs and neon signs work in this way. Each element has its own characteristic set of lines, and molecules can also produce...

the de broglie wavelength

Electron Waves and Standing Orbits

Electron waves and standing orbits explain how tiny particles can behave like waves. Large objects in the macroscopic world, like a billiard ball on a table, follow classical physics. A ball keeps moving in a straight line unless it hits another ball or a force such as friction acts on it. It also has a well-defined position, velocity, and momentum, where momentum is mass times velocity. Waves behave differently from macroscopic particles. When waves interact, they can form interference...

the uncertainty principle

Electron Position and Momentum Limits

Heisenberg’s uncertainty principle sets a limit on how precisely we can know an electron’s position and momentum at the same time. Momentum is the motion of a particle, and the two measurements affect each other. If the momentum is known more accurately, the position becomes less certain, and the reverse is also true. Heisenberg described this limit with an equation that uses Planck’s constant. The equation shows the smallest possible uncertainty for position and momentum together. It explains...

the quantum-mechanical model of an atom

Electron Orbitals in Quantum Mechanics

Quantum mechanics explains how electrons behave in atoms using waves and probability. Erwin Schrödinger built on de Broglie’s idea that an electron in hydrogen could act like a circular standing wave instead of moving in fixed circular paths. He then derived the Schrödinger equation, which became a major step in modern atomic theory. When Schrödinger applied his equation to hydrogen-like atoms, it matched Bohr’s energy expression and the Rydberg formula for hydrogen spectra. He described...

quantum numbers

Electron Orbitals and Spin

Electron orbitals are described by quantum numbers that show where an electron is most likely to be found around the nucleus. These numbers come from the quantum mechanical model, which is based on solutions of the Schrödinger equation. They also help explain why electron energy comes in set values instead of changing smoothly. The principal quantum number, n, labels the energy level. It can be 1, 2, 3, and so on, and higher n values usually mean higher electron energy. This number also tells...

atomic orbitals

Electron Regions in Atomic Orbitals

Electron regions in atomic orbitals show where an electron is most likely to be found in an atom. These three-dimensional regions are often drawn as boundary surfaces around the densest part of the cloud. The shape of an orbital depends on the angular momentum quantum number, l. This value can range from 0 to n - 1, where n is the principal quantum number. For n = 1, only l = 0 is allowed. For n = 2, both l = 0 and l = 1 are allowed. Orbitals with the same value of l form a subshell. The l =...

the pauli exclusion principle

Electron Spin and Orbital Pairing

Electron spin and orbital pairing explain why only two electrons can fit in one atomic orbital. Electron configuration describes how electrons are arranged in an atom’s orbitals. It is written with three parts: the principal quantum number, n, the orbital type, or subshell, and a superscript that shows how many electrons are in that subshell. For example, 2p4 means four electrons in a p subshell with n = 2, and 3d8 means eight electrons in a d subshell with n = 3. The three quantum numbers...

the energies of atomic orbitals

Shielding and Orbital Penetration

Shielding and orbital penetration help explain why electrons in an atom have different energies. Electrons are attracted to the positive nucleus, but they also repel one another in atoms with more than one electron. The strength of these forces depends on the charge and the distance between the particles. Opposite charges attract, like charges repel, and the force gets weaker as the particles move farther apart. An electron that stays closer to the nucleus is held more tightly. That means...

the aufbau principle and hund's rule

Electron Filling Order in Atomic Orbitals

Electron filling order in atomic orbitals follows the aufbau principle and Hund's rule. To write an electron configuration, we build atoms in order of atomic number. Starting with hydrogen and moving across the periods of the periodic table, one proton is added to the nucleus and one electron is placed into the correct subshell. This process describes the ground-state electron configurations of the elements. The aufbau principle comes from the German word aufbau, which means "to build up." It...

electron configuration of multielectron atoms

electron-configuration-of-multielectron-atoms

Valence Electrons and Noble Gas Shorthand

Valence electrons and noble gas shorthand help show how electrons are arranged in multielectron atoms. Sodium, the alkali metal with atomic number 11, has one more electron than neon. That extra electron goes into the lowest-energy subshell available, the 3s orbital, so sodium has the configuration 1s2 2s2 2p6 3s1. Electrons in the outermost shell, where n is highest, are called valence electrons. Electrons in the inner shells are called core electrons. Because core electrons often match a...

key terms and concepts

Explore how heated gases produce line spectra, why hydrogen shows discrete wavelengths, and how Rydberg and Bohr helped explain emission lines.

Line Spectra from Heated Gases | JoVE K12

chemistry

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Pennsylvania State Academic Standards

Earth and Space Science

Space Systems

3.3.9-12.B

3.3.9-12.C

Louisiana Student Standards for Science

High School

Earth Science

Earth’s Place In The Universe

HS-ESS1-1

HS-ESS1-2

motion-and-stability-forces-and-interactions

Motion And Stability: Forces And Interactions

HS-PS2-6

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Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Atoms

Tennessee Academic Standards

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Waves and Their Applications in Technologies for Information Transfer

CHEM1.PS4.1

Virginia  Standards of Learning

HIgh School

CH.2

CH.2.e

PS.2

PS.2.a

Arizona Science Standards

HS+C.P1

HS+C.P1U1.2

Texas Essential Knowledge and Skills

CHEM.6

CHEM.6.A

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CHEM.6.C

Alabama Course of Study Science

Matter and Its Interactions

9-12.C.1.1.c

Earth's Place in the Universe

9-12.ESS.1.1.b

9-12.ESS.1.2

9-12.ESS.1.2.c

9-12.ESS.1.3.a

Next Generation Science Standards

Earth’s Place in the Universe

Florida Department of Education

SC.912.E.5

SC.912.E.5.8

SC.912.P.8

SC.912.P.8.3

SC.912.P.10

SC.912.P.10.9

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PHYS.8

PHYS.8.F

PHYS.9

PHYS.9.A

Chemistry and Physics

IPC.7

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South Carolina College and Career Ready Science Standards

C-PS4-5

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new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Chemical Reactions

HS-PS1-7.

Georgia Standards of Excellence

SC1.

Light Emission and Electron Movement

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
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Elements: Chemical Symbols and Isotopes

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Molecules and Compounds

Atoms and Molecules

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Solution Formation

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Colloids

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Construct an explanation to classify matter as a pure substance or mixture; homogeneous or heterogeneous; element or compound; solution, colloid or suspension.

PS.PSc.1.1

Phase Transitions

Whether solid, liquid, or gas, a substance&#39;s state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the ...

phase-transitions-vaporization-and-condensation

Phase Transitions: Vaporization and Condensation

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Vapor Pressure

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Clausius-Clapeyron Equation

The equilibrium between a liquid and its vapor depends on the temperature of the system; a rise in temperature causes a corresponding rise in the vapor ...

Phase Transitions: Melting and Freezing

Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy ...

phase-transitions-sublimation-and-deposition

Phase Transitions: Sublimation and Deposition

Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and ...

Heating and Cooling Curves

When a substance&#8212;isolated from its environment&#8212;is subjected to heat changes, corresponding changes in temperature and phase of the substance ...

Phase Diagrams

A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. ...

Use models to compare the phases of matter and the physical changes they undergo.

PS.PSc.1.2

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

comparing-intermolecular-forces-melting-point-boiling-point

Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility

Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

Carry out investigations to compare physical and chemical properties of matter.

PS.PSc.1.3

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

Use models to interpret the data presented in Bohr diagrams and electron dot diagrams for neutral atoms of elements 1 through 18.

Understand types, properties, and structure of matter.

Line Spectra from Heated Gases

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