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

I legami chimici tengono insieme gli atomi di una molecola o di un composto. I legami si formano quando gli elettroni nel guscio di valenza dell'atomo vengono donati o condivisi con altri atomi.
Ad esempio, i legami ionici si formano quando gli atomi donano o accettano elettroni, riempiendo il loro guscio di valenza. Un atomo che dona elettroni e si carica positivamente è un catione, mentre uno che accetta elettroni e si carica negativamente è un anione.
Nel sale da cucina, l'associazione tra il catione sodio e l'anione cloruro è un legame ionico.
I legami covalenti si formano tra atomi che condividono reciprocamente una o più coppie di elettroni di valenza.
Ad esempio, due atomi di idrogeno possono condividere una coppia di elettroni, formando un singolo legame covalente. L'ossigeno e l'azoto possono condividere due o tre coppie di elettroni, formando doppi e tripli legami.

introduzione ai legami chimici

Introduction to Chemical Bonds

I legami chimici Gli elettroni del livello energetico piesterno determinano la stabilitenergetica dell'atomo e la sua tendenza a formare legami chimici con altri atomi. Il guscio elettronico piinterno ha una capacitmassima di due elettroni, ma i successivi due gusci elettronici possono ospitare ognuno un massimo di otto elettroni. Questo noto come regola dell'ottetto, che afferma che, ad eccezione del guscio piinterno, gli atomi sono pistabili energeticamente quando hanno otto elettroni nel loro guscio di valenza, il guscio elettronico piesterno. Tuttavia, poichnon tutti gli elementi hanno abbastanza elettroni per riempire i loro gusci piesterni, gli atomi formano legami chimici con altri atomi, ottenendo cosgli elettroni di cui hanno bisogno per avere una configurazione elettronica stabile. Pertanto, un legame chimico la forza che tiene insieme gli atomi in una molecola o un composto. Legami ionici Gli atomi possono guadagnare o perdere elettroni per riempire il loro guscio di valenza. In questo modo, diventano carichi elettricamente e vengono chiamati ioni. Un catione un atomo con carica positiva che perde elettroni, mentre un atomo che guadagna elettroni e diventa carico negativamente un anione. Le cariche opposte dei cationi e degli anioni esercitano una moderata attrazione reciproca che mantiene gli atomi in stretta vicinanza formando un legame ionico. Un legame ionico un'associazione continua tra ioni di carica opposta. Il sale da tavola comune deve la sua esistenza al legame ionico. Legami covalenti Un altro modo per soddisfare la regola dell'ottetto la condivisione di elettroni tra atomi per formare legami covalenti. Questi legami sono piforti e molto picomuni dei legami ionici nelle molecole degli organismi viventi. I legami covalenti si trovano comunemente nelle molecole organiche a base di carbonio, come il nostro DNA e le proteine. I legami covalenti si trovano anche nelle molecole inorganiche come l'acqua, il biossido di carbonio e l'ossigeno. Legami idrogeno Un legame idrogeno si forma quando un atomo di idrogeno debolmente positivo gilegato ad un altro atomo elettronegativo (ad esempio, l'ossigeno nella molecola di acqua) viene attratto da un altro atomo elettronegativo proveniente da un'altra molecola. L'esempio picomune di legame idrogeno nel mondo naturale avviene tra molecole di acqua. Accade ogni volta che due gocce di pioggia si fondono in una goccia pigrande o un corso d'acqua si riversa in un fiume. Il legame idrogeno si verifica perchl'atomo di ossigeno debolmente negativo in una molecola d'acqua attratto dagli atomi di idrogeno debolmente positivi di altre due molecole d'acqua. Questo testo parzialmente adattato da <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>

Introduzione ai legami chimici

Legami chimici
Gli elettroni del livello energetico più esterno determinano la stabilità energetica dell'atomo e la sua tendenza a formare legami chimici con ...

Education

Didattica

JoVE Core

Anatomy and Physiology

Anatomia e Fisiologia

Unit 1

Unità 1

Fundamentals of Chemistry

Fondamenti di Chimica

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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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Matter is the substance that makes up the universe, from a grain of sand to a star. Scientists define matter as anything that occupies space and has mass. Mass is the amount of matter in an object, while weight depends on gravity. Mass stays the same whether an object is on Earth or in the zero-gravity environment of outer space. Weight changes when gravity changes. An object weighs more where gravity is stronger and less where gravity is weaker. A piece of cheese that weighs a pound on Earth...

the periodic table and organismal elements

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Organismal Elements in the Periodic Table

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atomic structure

From Atomos to the Modern Atom

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chemical symbols

Chemical Symbols and Element Names

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atomic number and mass number

Atomic Identity, Mass, and Isotopes

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atomic weight

Atomic Mass and Mole Calculations

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isotopes and radioisotopes

Radioisotopes in Medicine and Imaging

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electron behavior

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...

introduction to chemical bonds

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ionic bonds

Ionic Bonds and Charge Transfer

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covalent bonds

Polar and Nonpolar Covalent Bonds

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hydrogen bonds

Hydrogen Bonding and DNA Stability

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ions, molecules, and compounds

Atomic Charges, Bonds, and Compounds

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states of matter

Solids, Liquids, Gases, and Plasma

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colloids and suspensions

Suspensions, Sedimentation, and Colloids

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introduction to chemical reactions

Chemical Reaction Basics and Equilibrium

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Anabolism, Catabolism, and ATP Use

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types of chemical reactions: exchange and reversible

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Electron Transfer and Chemical Equilibrium

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Chemical Energy and Reaction Types

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factors influencing the rate of chemical reactions

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Chemical Reaction Rates and Catalysts

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acids, bases and neutralization reactions

How pH Affects Cells and Digestion

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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

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.

How Atoms Bond to Reach Stability

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