Name: atomic charges, bonds, and compounds
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 23 s
Channel: JoVE

Gli ioni sono atomi caricati elettricamente che hanno guadagnato o perso elettroni. Un atomo che perde elettroni e si carica positivamente è un catione, mentre un atomo che guadagna elettroni e si carica negativamente è un anione.
Gli ioni sono vitali per molti processi fisiologici, come la trasmissione degli impulsi nervosi e la contrazione muscolare.
Le molecole sono combinazioni di due o più atomi che condividono elettroni. Possono essere costituiti da atomi di un elemento, come una molecola di ossigeno, o da atomi di elementi diversi, come una molecola d'acqua.
Un composto è una combinazione di atomi di diversi elementi legati chimicamente in una proporzione fissa, indipendentemente dal fatto che gli elettroni siano trasferiti o condivisi.
I composti ionici sono formati dall'interazione elettrostatica tra ioni metallici e non metallici, come nel normale sale da cucina, con un catione sodio e un anione cloruro legati insieme tramite interazioni elettrostatiche.
I composti molecolari si formano quando atomi non metallici sono legati tramite legami covalenti. Ad esempio, il metano è un composto molecolare in cui quattro atomi di idrogeno condividono elettroni con un atomo di carbonio in una proporzione specifica.

ioni, molecole e composti

Gli ioni - Quando un atomo partecipa a una reazione chimica che comporta la donazione o l'accettazione di uno o pielettroni, l'atomo diventa caricato positivamente o negativamente. Questo accade spesso affinchla maggior parte degli atomi abbia un guscio di valenza completo. Cipuavvenire sia guadagnando elettroni per riempire un guscio che pidella metpieno, sia donando elettroni per svuotare un guscio che meno della metpieno, lasciando cosil successivo guscio elettronico pipiccolo come il nuovo guscio di valenza completa. Un atomo con una carica elettrica - positiva o negativa - uno ione. Il potassio (K), ad esempio, un elemento importante in tutte le cellule del corpo. Il suo numero atomico 19. Ha solo un elettrone nel suo guscio di valenza. Questa caratteristica rende il potassio molto propenso a partecipare a reazioni chimiche in cui dona un elettrone. La perdita farsche la carica positiva dei protoni del potassio sia piinfluente della carica negativa degli elettroni del potassio. In altre parole, il risultante ione di potassio sarleggermente positivo. Un ione con carica positiva chiamato un catione. Un altro elemento, il fluoro (F), un componente delle ossa e dei denti, ha un numero atomico di nove. Ha sette elettroni nel suo guscio di valenza. Il fluoro ha una grande probabilitdi legarsi ad altri atomi in modo tale da accettare un elettrone. Quando lo fa, gli elettroni del fluoro superano i protoni per uno, e lo ione avruna carica complessivamente negativa. Un ione con carica negativa chiamato un anione. Gli ioni sono fondamentali per il normale funzionamento del corpo, quindi i loro squilibri possono causare problemi di salute. Ad esempio, uno squilibrio degli ioni di sodio potrebbe causare malattie cardiovascolari. Bassi livelli di calcio nel sangue possono causare tetania - contrazioni muscolari involontarie incontrollabili. Molecole - Le molecole consistono semplicemente in due o piatomi legati chimicamente insieme. Le molecole possono essere composte da atomi dello stesso elemento, come una molecola di ossigeno gassoso, formata dalla legatura tra due atomi di ossigeno, oppure possono essere formate dalla legatura tra atomi di elementi diversi, come una molecola di anidride carbonica, formata tra atomi di ossigeno e carbonio. Composti - Un composto una sostanza pura formata dalla legatura di due o piatomi in una proporzione fissa. Ad esempio, il glucosio un importante combustibile per il corpo. sempre composto dagli stessi tre elementi: carbonio, idrogeno e ossigeno, nelle stesse quantitrelative. Nel glucosio, ci sono sempre sei unitdi carbonio e sei unitdi ossigeno per ogni dodici unitdi idrogeno. Questo testo parzialmente adattato da <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-2-chemical-bonds?query=when%20a%20atom%20participates&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-id2113058">Openstax, Anatomy and Physiology 2e, Section 2.2 Chemical Bonds</a> and Openstax, <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-1-elements-and-atoms-the-building-blocks-of-matter?query=For%20example%2C%20the%20compound%20glucose%20is%20an%20important%20body%20fuel.%20It%20is%20always%20composed%20of%20the%20same%20three%20elements&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-id1882474">Anatomy and Physiology 2e, Section 2.1 Elements and Atoms: The Building Blocks of Matter</a>.

Ioni, Molecole e Composti

Ioni - Quando un atomo partecipa a una reazione chimica che si traduce nella donazione o accettazione di uno o più elettroni, l'atomo diventa positivamente ...

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

Ions, Molecules, and Compounds

atomic charges, bonds, and compounds

Atoms can gain or lose electrons during chemical reactions and become ions. An ion is an atom with an electrical charge. This charge is positive or negative, and it often helps the atom reach a full valence shell.

Some atoms are more likely to donate electrons, while others are more likely to accept them. Potassium is one example. It has atomic number 19 and one electron in its valence shell, so it is likely to donate that electron and become a slightly positive ion called a cation. Fluorine is another example. It has atomic number 9 and seven electrons in its valence shell, so it is likely to accept one electron and become a negatively charged ion called an anion.

Ions are important for normal body function, so an imbalance can cause health problems. A sodium ion imbalance can contribute to cardiovascular diseases. Low blood calcium levels can also cause tetany, which is marked by uncontrollable involuntary muscle contractions.

Molecules and compounds are related but not the same. A molecule is two or more atoms chemically bonded together. The atoms may be the same element, as in oxygen gas, or different elements, as in carbon dioxide gas. A compound is a pure substance made when two or more atoms bond in a fixed proportion.

Glucose is a useful example of a compound. It is an important body fuel and always contains the same elements in the same relative amounts: carbon, hydrogen, and oxygen. In glucose, there are always six carbon units and six oxygen units for every twelve hydrogen units.

Atomic Charges, Bonds, and Compounds

what is matter?

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the periodic table and organismal elements

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Organismal Elements in the Periodic Table

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atomic structure

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chemical symbols

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Chemical symbols are short abbreviations that stand for an element or a single atom of that element. Mercury, for example, has the symbol Hg. The same symbol can point to one atom of mercury in the microscopic domain or to a sample labeled as many atoms of mercury in the macroscopic domain. Many symbols come from the element’s common name. Others are shortened from a name in another language. Most chemical symbols use one or two letters. For a few elements with atomic numbers above 112,...

atomic number and mass number

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atomic weight

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Atomic mass and mole calculations help explain how much matter is in atoms and compounds. Protons and neutrons have about the same mass, about 1.67 × 10 -24 grams. Scientists define that mass as one atomic mass unit, or amu, also called one Dalton. Electrons are much lighter than protons. They weigh only 9.11 × 10 -28 grams, or about 1/1800 of an atomic mass unit. Because of that small mass, electrons do not add much to an element’s overall atomic mass. When chemists calculate atomic mass,...

isotopes and radioisotopes

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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

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...

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

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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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types of chemical reactions: anabolic and catabolic

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Anabolism, Catabolism, and ATP Use

Anabolism and catabolism are the two main kinds of metabolic reactions in the body. Metabolism is the total set of anabolic and catabolic reactions that keep life running. These reactions follow the first law of thermodynamics, which says energy cannot be created or destroyed. It can only change form. Anabolism builds larger, more complex molecules from smaller ones. These anabolic, or biosynthesis, reactions need energy in the form of ATP. They join monosaccharides into polysaccharides, fatty...

types of chemical reactions: exchange and reversible

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Electron Transfer and Chemical Equilibrium

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energy transfer in chemical reactions

Chemical Energy and Reaction Types

Chemical reactions depend on energy transfer, chemical bonds, and the way matter collides. A reaction needs enough energy for particles to meet with the right force and precision. That energy can break old bonds and help form new ones. Kinetic energy is the energy of motion. A person lifting a brick uses kinetic energy to move the brick into place on a wall. Once the wall is built, it stores potential energy, which is the energy of position or structure. If the wall falls, that stored energy...

factors influencing the rate of chemical reactions

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Chemical Reaction Rates and Catalysts

Chemical reaction rates depend on how often particles collide and whether those collisions have enough energy to start a reaction. That starting energy is called activation energy. Factors that affect reaction rate either lower that energy or make successful collisions more likely. Concentration and pressure can speed reactions up because they put more particles in the same space. When more particles are present, they are more likely to bump into one another. Chemists can also increase...

acids, bases and neutralization reactions

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Acids, bases, and pH help control how cells and body systems work. In biology, pH can strongly affect enzymes, proteins, and nucleic acids. Enzymes work best within a certain pH range, and pH changes can alter their structure or denature them, which changes how they function. Acids release hydrogen ions, or H+, in solution. A hydrogen ion is a proton, so it is very reactive in chemical reactions. Strong acids release all of their H+ in water and ionize completely. Hydrochloric acid (HCl) is a...

key terms and concepts

Learn how atoms become ions, why cations and anions form, and how molecules and compounds differ using potassium, fluorine, oxygen, carbon dioxide, and glucose.

Atomic Charges, Bonds, and Compounds | 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.

Atomic Charges, Bonds, and Compounds

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