Name: how atoms bond to reach stability
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 1 s
Channel: JoVE

Химические связи удерживают атомы молекулы или соединения вместе. Связи образуются, когда электроны в валентной оболочке атома отдают или делятся с другими атомами.
Например, ионные связи образуются, когда атомы отдают или принимают электроны, заполняя свою валентную оболочку. Атом, который отдает электроны и становится положительно заряженным, является катионом, в то время как атом, который принимает электроны и становится отрицательно заряженным, является анионом.
В поваренной соли связь между катионом натрия и анионом хлорида представляет собой ионную связь.
Ковалентные связи образуются между атомами, которые взаимно разделяют одну или несколько пар валентных электронов.
Например, два атома водорода могут делить пару электронов, образуя одну ковалентную связь. Кислород и азот могут делить две и три электронные пары, образуя двойные и тройные связи.

Введение в Химические Связи

Introduction to Chemical Bonds

Химические связи

Электроны внешнего энергетического уровня определяют энергетическую стабильность атома и его склонность образовывать химические связи с другими атомами. Внутренняя оболочка электронов имеет максимальную вместительность в два электрона, но следующие две оболочки электронов могут содержать максимум восемь электронов. Это известно как правило октета, которое утверждает, что, за исключением внутренней оболочки, атомы наиболее энергетически стабильны, когда у них в валентной оболочке, внешней оболочке электрона, восемь электронов.

Однако, так как не все элементы имеют достаточное количество электронов для заполнения своих внешних оболочек, атомы образуют химические связи с другими атомами, тем самым получая необходимые им электроны для достижения стабильной электронной конфигурации. Поэтому химическая связь – это сила, которая держит атомы вместе в молекуле или соединении.

Ионные связи

Атомы могут получать или отдавать электроны для заполнения своей валентной оболочки. При этом они электрически заряжаются и называются ионами. Катион – это положительно заряженный атом, который теряет электроны, в то время как атом, который получает электроны и становится отрицательно заряженным, называется анионом. Противоположные заряды катионов и анионов оказывают умеренно сильное взаимное притяжение, которое поддерживает атомы близко друг к другу, образуя ионную связь. Ионная связь – это продолжающееся близкое взаимодействие между ионами с противоположным зарядом. Обычная поваренная соль существует благодаря ионной связи.

Ковалентные связи

Другой способ удовлетворения правила октета - это совместное использование электронов между атомами для образования ковалентных связей. Эти связи являются более прочными и намного более распространёнными, чем ионные связи в молекулах живых организмов. Ковалентные связи обычно встречаются в органических молекулах на основе углерода, таких как наша ДНК и белки. Ковалентные связи также встречаются в неорганических молекулах, таких как вода, диоксид углерода и кислород.

Водородные связи

Водородная связь образуется, когда слабо положительный атом водорода, уже связанный с одним электронегативным атомом (например, кислородом в молекуле воды), притягивается к другому электронегативному атому из другой молекулы. Самый распространенный пример водородной связи в природе происходит между молекулами воды. Это происходит, когда две капли дождя объединяются в одну большую или ручей вливается в реку. Водородная связь возникает потому, что слабо отрицательный атом кислорода одной молекулы воды притягивается к слабо положительным атомам водорода двух других молекул воды.

Адаптированная версия текста <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-2-chemical-bonds?query=chemical%20bond&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-id1493624">Openstax, Anatomy and Physiology 2e, Section 2.2: Chemical Bonds.</a> <a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=chemical%20bonds">Openstax, </a><a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=chemical%20bonds">Biology for AP® Courses</a><a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=chemical%20bonds"> Section </a><a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=chemical%20bonds">2.1 Atoms, Isotopes, Ions, and Molecules: The Building Blocks.</a>

Химические связи
Электроны самого внешнего энергетического уровня определяют энергетическую стабильность атома и его склонность к образованию химических связей с ...

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

how atoms bond to reach stability

Atoms bond to become more stable, and their outermost electrons play the biggest role in that process. The inner electron shell can hold two electrons. The next two shells can each hold eight electrons. This is called the octet rule. It states that, except for the innermost shell, atoms are most stable when their valence shell, or outer shell, has eight electrons.

When atoms do not have enough electrons to fill that outer shell, they form chemical bonds with other atoms. A chemical bond is the force that holds atoms together in a molecule or compound. These bonds let atoms reach a more stable electron arrangement.

One common type is an ionic bond. In this case, atoms gain or lose electrons to fill their valence shell. When they do this, they become ions. A cation is a positively charged ion that has lost electrons. An anion is a negatively charged ion that has gained electrons. The opposite charges attract each other and keep the ions close together. This close association forms an ionic bond. Table salt is a common example of a substance made through ionic bonding.

Another way atoms satisfy the octet rule is by sharing electrons. This creates covalent bonds. Covalent bonds are stronger and much more common than ionic bonds in the molecules of living organisms. They are found in carbon-based organic molecules such as DNA and proteins. They also occur in inorganic molecules like water, carbon dioxide, and oxygen.

Hydrogen bonds are a weaker kind of attraction. They form when a weakly positive hydrogen atom, already bonded to another electronegative atom such as oxygen, is attracted to a different electronegative atom in another molecule. Water is the most common example. Hydrogen bonding helps explain why raindrops can merge into larger beads and why a creek can flow into a river.

How Atoms Bond to Reach Stability

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Ionic Bonds and Charge Transfer

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key terms and concepts

Learn how atoms use ionic, covalent, and hydrogen bonds to reach stability. Explore valence electrons, ions, and examples like salt and water.

How Atoms Bond to Reach Stability | JoVE K12

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How Atoms Bond to Reach Stability

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