Name: electron shells and discovery
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 9 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Chemistry

Matter And Its Interactions

HS-PS1-1

Electron Behavior

Электроны — это крошечные, отрицательно заряженные частицы, которые существуют в электронном облаке вокруг положительно заряженного ядра. Внутри облака электроны находятся в отдельных областях, называемых оболочками или энергетическими уровнями.
Энергетические уровни часто визуализируются с помощью упрощенной модели Бора или планетарной модели, где они представлены в виде колец вокруг ядра, хотя на самом деле они имеют сложную форму.
Электроны в этих оболочках имеют возрастающую энергию по мере удаления от ядра.
На первом энергетическом уровне может быть максимум два электрона. Вторая оболочка может содержать максимум восемь электронов. Дополнительные электроны в атоме заполняют все более высокие энергетические уровни.
Электроны в самой внешней занятой оболочке называются валентными электронами и определяют химические свойства элемента.
Валентные электроны могут разделяться между атомами с образованием ковалентных связей или переноситься с образованием ионных связей.

Поведение электронов

Электроны – это отрицательно заряженные субатомные частицы, притягивающиеся и орбитально вращающиеся вокруг положительно заряженного ядра атома. Они находятся в пространствах, связанных с энергетическими уровнями, называемыми оболочками, и дополнительно организованы в подоболочки и орбитали внутри каждой оболочки.

Электроны связаны с ядром и образуют орбиты

Электроны находятся в определённых местах вне ядра. Оболочка, в которой находится электрон, указывает на общий энергетический уровень электрона: те, которые находятся ближе к ядру, имеют меньше энергии, в то время как те, которые находятся дальше, имеют больше энергии. Подоболочка более точно описывает местоположение и уровень энергии электрона, а орбиталь описывает форму области вероятности, в которой электрон орбитально вращается вокруг ядра. Электроны, находящиеся ближе к ядру, имеют наименьшее количество энергии, и по мере увеличения расстояния от ядра, количество энергии, которое несёт электрон, также увеличивается. Чем дальше от ядра, тем больше пространства для орбиты электронов, поэтому внешние оболочки могут содержать больше электронов, чем внутренние оболочки. Самые внешние электроны атома находятся в валентной оболочке и называются валентными электронами. Эти электроны могут образовывать ионные и ковалентные связи с другими атомами.

Открытие электрона

В конце 1890-х годов Дж. Дж. Томсон провел серию экспериментов с использованием катодно-лучевых трубок, которые привели к открытию электрона - первой субатомной частицы. Катодно-лучевая трубка – это стеклянная трубка с двумя электродами, подключенными к источнику питания, подающему электричество. Внутреннее пространство трубки освобождается от большей части воздуха. Когда напряжение подается на электроды, пучок частиц движется от отрицательно заряженного катода к положительно заряженному аноду. У анода есть маленькое отверстие, чтобы лучи могли проходить. Фосфорное покрытие на противоположном конце трубки светится, когда на него попадают катодные лучи.

Томсон направил катодный луч между двумя металлическими пластинами, одна из которых имела положительный заряд, а другая – отрицательный, и измерил положение луча на дальнем конце трубки. Когда луч проходил между двумя пластинами, он отклонялся от отрицательно заряженной пластины, сгибаясь в направлении положительно заряженной пластины. Поскольку одинаковые заряды отталкиваются, а разноимённые притягиваются, это указывало на то, что частицы в катодном луче обладали отрицательным зарядом.

Дальнейшие эксперименты для вычисления отношения массы к заряду катодных частиц показали, что масса каждой отрицательно заряженной частицы была около 1/2000 массы любого известного атома. Из-за этого Томсон сделал вывод, что в любом данном атоме должно быть много электронов. Позже, открытие протонов и нейтронов объяснило распределение массы атома и его общий нейтральный заряд.

Адаптированная версия текста <a href="https://openstax.org/books/chemistry-2e/pages/6-3-development-of-quantum-theory#0">Openstax, Chemistry 2e, Section 6.3: Development of quantum theory</a>.

Электроны — это отрицательно заряженные субатомные частицы, притягивающиеся к положительно заряженному ядру атома и вращающиеся вокруг него. Они обитают в пространствах...

Education

JoVE Core

Anatomy and Physiology

Анатомия и физиология

Unit 1

Раздел 1

Fundamentals of Chemistry

Основы химии

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

electron shells and discovery

Electrons are negatively charged subatomic particles that stay near the positively charged nucleus of an atom. They occupy spaces linked to energy levels called shells. They are also arranged into subshells and orbitals within each shell.

An electron’s shell shows its general energy level. Electrons closer to the nucleus have less energy, while electrons farther away have more energy. The outer shells have more space, so they can hold more electrons than the inner shells.

Subshells describe an electron’s location and energy more precisely. Orbitals describe the shape of an area of probability where an electron may move around the nucleus. The outermost electrons are found in the valence shell and are called valence electrons. These electrons can form ionic and covalent bonds with other atoms.

J. J. Thomson discovered the electron in the late 1890s through experiments with cathode ray tubes. A cathode ray tube is a glass tube with two electrodes, a power source, and a vacuum that removes most of the air. When voltage is applied, a beam of particles travels from the negatively charged cathode to the positively charged anode, and a phosphorus coating glows when the beam strikes it.

Thomson also sent the cathode ray between two metal plates, one positive and one negative. The ray bent away from the negatively charged plate and toward the positively charged plate. This showed that the particles carried a negative charge, since like charges repel and opposite charges attract.

Further experiments showed that each particle had a mass about 1/2000 of the mass of any known atom. Thomson concluded that atoms must contain many electrons. Later, the discovery of protons and neutrons helped explain how an atom’s mass is spread out and why its overall charge is neutral.

Electron Shells and Discovery

what is matter?

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isotopes and radioisotopes

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Solids, Liquids, Gases, and Plasma

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colloids and suspensions

Suspensions, Sedimentation, and Colloids

Suspensions and colloids are two common kinds of mixtures seen in everyday life. Mud and water, flour and water, and tempera paint are suspensions. These mixtures are heterogeneous, which means their particles are not spread out evenly. The particles are relatively large and can be seen with the naked eye or a magnifying glass. Suspension particles make mixtures cloudy, and they settle out after mixing. The settling of particles in a suspension is called sedimentation. A blood test can measure...

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factors influencing the rate of chemical reactions

factors-influencing-the-rate-of-chemical-reactions

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acids, bases and neutralization reactions

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key terms and concepts

Explore how electrons are arranged in shells, subshells, and orbitals, and how J. J. Thomson discovered the electron using cathode ray tubes.

Electron Shells and Discovery | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

motion-and-stability-forces-and-interactions

Motion And Stability: Forces And Interactions

HS-PS2-6

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

Physics

Motion and Stability: Forces and Interactions

P-PS2-6.

The Periodic Table

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Periodic Classification of the Elements

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The Periodic Table And Organismal Elements

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Electron Configurations

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Electronic Structure of Atoms


An atom comprises protons and neutrons, which are contained inside the dense, central&#160;core called the nucleus, with electrons present around the ...

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Electron Configuration of Multielectron Atoms

The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the ...

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Atomic Radii and Effective Nuclear Charge

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The Aufbau Principle and Hund's Rule

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Coulomb's Law

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Electric Charges

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Sources and Properties of Electric Charge

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Electric Fields

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Intermolecular Forces

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Van der Waals Interactions

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Chemical Bonds


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Electrons are negatively charged subatomic particles attracted to and orbit around the positively-charged nucleus of an atom. They reside in spaces ...

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 ...

Ions and Ionic Charges

In ordinary chemical reactions, the nucleus &mdash; which contains the protons and neutrons of each atom and thus identifies the element &mdash; remains ...

Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level and the composition of the nucleus of atoms.  Clarification Statement: Chemistry: Examples of properties that could be predicted from patterns could include reactivity of metals, types of bonds formed, numbers of bonds formed, atomic radius, atomic mass, or reactions with oxygen. Emphasis is on main group elements and qualitative understanding of the relative trends of ionization energy and electronegativity.

Properties of Transition Metals

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The Atomic Theory of Matter

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Temperature Dependence on Reaction Rate

The Collision Theory
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Stoichiometry, Product Yield, and Limiting Reactants

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Preparation of 25% v/v Ethylenediamine in Deionized WaterExpand
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A physical property is ...

Dynamic Equilibrium

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Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.  Clarification Statement: Chemistry: Examples of chemical reactions could include the reaction of sodium and chlorine, carbon and oxygen, or carbon and hydrogen. Reaction classification aids in the prediction of products (e.g. synthesis, decomposition, single displacement, double displacement, and acid-base).

HS-PS1-2

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Intermolecular Forces and Physical Properties



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HS-PS1-3

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Overview

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HS-PS1-4

Electron Shells and Discovery

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