Name: predicting ion charges on the periodic table
Uploaded: 2020-09-03T13:38:25.000Z
Duration: 3 min 27 s
Channel: JoVE

K12 Standards

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

North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

Matter and its Interactions

PS.PSc.1.5

Ions and Ionic Charges

Gli atomi sono particelle neutre con un numero uguale di protoni ed elettroni. Un elemento è definito dal numero di protoni, che non cambia;tuttavia, molti atomi possono guadagnare o perdere uno o più elettroni per diventare una particella carica. Quando un atomo o una molecola guadagna o perde elettroni, viene chiamato ione.

Gli elettroni, essendo di massa molto più piccola dei protoni, non contribuiscono in modo significativo alla massa atomica. Pertanto, la massa atomica di uno ione è essenzialmente la stessa della massa atomica dell'atomo neutro. Quando gli atomi o le molecole perdono elettroni, vengono chiamati cationi.

I cationi hanno una carica positiva perché hanno più protoni, che possiedono una carica positiva, rispetto agli elettroni, che hanno una carica negativa. Ai cationi viene dato lo stesso nome del loro elemento, seguito dalla parola ione. Un atomo di calcio ha 20 protoni e 20 elettroni.

Perde due elettroni per diventare uno ione calcio con 20 protoni e 18 elettroni. Poiché ora ha due cariche positive in più rispetto alle cariche negative, ha una carica complessiva di due positività. Il simbolo chimico di uno ione è scritto come il simbolo chimico dell'atomo, con la carica scritta in apice a destra.

Il simbolo chimico di uno ione di calcio è quindi scritto come C-a-due più. Quando gli atomi o le molecole guadagnano elettroni, sono chiamati anioni. Gli anioni hanno una carica negativa perché possiedono più elettroni che protoni.

Gli anioni vengono denominati aggiungendo il suffisso ide al nome dell'elemento. Un atomo di fluoro ha 9 protoni e 9 elettroni. Il fluoro guadagna un elettrone per diventare uno ione fluoruro con 9 protoni e 10 elettroni.

Poiché ora ha una carica negativa in più rispetto alle cariche positive, ha una carica complessiva negativa. Il simbolo chimico del fluoro è scritto come F meno;esso é solitamente omesso per gli ioni con una carica positiva o negativa. Gli atomi perderanno o guadagneranno un numero specifico di elettroni quando formano uno ione.

Molte delle cariche per gli ioni formate dai principali elementi del gruppo possono essere previste utilizzando la tavola periodica. I metalli, sul lato sinistro della tavola periodica, perderanno elettroni. I metalli alcalini del gruppo 1 perdono tutti un elettrone e hanno una carica positiva quando diventano uno ione.

I metalli alcalino-terrosi del gruppo 2 perdono due elettroni e hanno due cariche positive. I non metalli, sul lato destro della tavola periodica, guadagneranno elettroni. Gli alogeni del gruppo 17 guadagnano un elettrone e hanno una carica negativa.

I gruppi 16 elementi guadagnano due elettroni e avranno una carica negativa di due. Molti metalli di transizione possono formare cationi con cariche diverse. I gas nobili del gruppo 18 generalmente non formano ioni.

<ol>
	<li>Jensen, William B. "La corretta scrittura delle cariche ioniche". Journal of Chemical Education 89, n. 8 (2012): 1084-1085.</li>
	<li>Schmid, Roland. "La configurazione dei gas nobili: non la forza motrice, ma la regola del gioco in chimica." Journal of chemical education 80, n. 8 (2003): 931.</li>
	<li>Gillespie, Ronald J. "Densità di elettroni, cariche atomiche e legami ionici, covalenti e polari". Journal of Chemical Education 78, n. 12 (2001): 1688. 
	 </li>
</ol>

ioni e cariche ioniche

Nelle reazioni chimiche ordinarie, il nucleo, che contiene i protoni e i neutroni di ciascun atomo e quindi identifica l’elemento, rimane invariato. Gli elettroni, tuttavia, possono essere aggiunti agli atomi tramite trasferimento da altri atomi, persi durante il trasferimento ad altri atomi o condivisi con altri atomi. Il trasferimento e la condivisione degli elettroni tra gli atomi governano la chimica degli elementi. Durante la formazione di alcuni composti, gli atomi acquistano o perdono elettroni per formare particelle caricate elettricamente, chiamate ioni.

Quando un atomo perde elettroni forma uno ione positivo, chiamato catione. I cationi hanno più protoni che elettroni. Allo stesso modo, quando un atomo acquista elettroni forma uno ione negativo, chiamato anione. Gli anioni hanno più elettroni che protoni.

La tavola periodica aiuta a prevedere se un atomo formerà un anione o un catione, e anche la carica dello ione risultante. Muovendosi dall'estrema sinistra verso destra nella tavola periodica, gli atomi dei metalli del gruppo principale perdono abbastanza elettroni da lasciare loro lo stesso numero di elettroni di un atomo del gas nobile precedente. Formano cationi con carica pari al numero del gruppo. Per esempio, un atomo di un metallo alcalino (Gruppo 1) perde un elettrone e forma un catione con carica 1+; un metallo alcalino terroso (Gruppo 2) perde due elettroni e forma un catione con carica 2+, e così via. Ad esempio, un atomo di calcio neutro, con 20 protoni e 20 elettroni, perde facilmente due elettroni. Ciò si traduce in un catione con 20 protoni, 18 elettroni e una carica 2+. Ha lo stesso numero di elettroni degli atomi del gas nobile precedente, l'argon, ed è simboleggiato da Ca^2+. Il nome di uno ione metallico è lo stesso del nome dell'atomo di metallo da cui si forma, quindi Ca^2+ è chiamato ione calcio.

Muovendosi dall'estrema destra verso sinistra nella tavola periodica, gli atomi degli elementi non metallici generalmente guadagnano abbastanza elettroni da dare loro lo stesso numero di elettroni di un atomo del gas nobile successivo nella tavola periodica. Formano anioni con carica negativa pari al numero dei gruppi spostati a sinistra dai gas nobili. Ad esempio, gli atomi degli elementi del gruppo 17 (un gruppo a sinistra dei gas nobili) acquistano un elettrone e formano anioni con carica 1−; gli atomi degli elementi del gruppo 16 (due gruppi a sinistra) acquistano due elettroni e formano ioni con carica 2−, e così via. Ad esempio, l'atomo neutro di bromo, con 35 protoni e 35 elettroni, può guadagnare un elettrone per fornirgli 36 elettroni. Ciò si traduce in un anione con 35 protoni, 36 elettroni e carica 1−. Ha lo stesso numero di elettroni degli atomi del successivo gas nobile, il kripton, ed è simboleggiato da Br^−.

In molti casi l'andamento tra la carica dello ione e la posizione del gruppo sulla tavola periodica può essere utilizzato come guida. Tuttavia, il suo valore predittivo diminuisce quando ci si sposta verso il centro della tavola periodica. I metalli di transizione e alcuni altri metalli spesso presentano cariche variabili che non sono prevedibili in base alla loro posizione nella tabella. Ad esempio, il rame può formare ioni con carica 1+ o 2+, mentre il ferro può formare ioni con carica 2+ o 3+.

Questo testo è adattato da <a href="https://openstax.org/books/chemistry-2e/pages/2-6-molecular-and-ionic-compounds">Openstax, Chemistry 2e, Section 2.6: Molecular and Ionic Compounds.</a>

Ioni e cariche ioniche

Nelle reazioni chimiche ordinarie, il nucleo - che contiene i protoni e i neutroni di ciascun atomo e quindi identifica l'elemento - rimane ...

Education

Didattica

JoVE Core

Chemistry

Chimica

Atoms and Elements

Atomi ed Elementi

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

predicting ion charges on the periodic table

Ion charges can often be predicted from an element’s position on the periodic table. In chemical reactions, the nucleus stays unchanged, but electrons may be transferred, lost, or shared. When atoms gain or lose electrons during compound formation, they become ions, which are electrically charged particles.

A positive ion is called a cation. A cation has more protons than electrons because it lost electrons. A negative ion is called an anion. An anion has more electrons than protons because it gained electrons.

The periodic table gives useful clues about ion charge. Main-group metals on the far left usually lose electrons until they have the same number of electrons as the preceding noble gas. Their cation charge often matches the group number. For example, a Group 1 alkali metal forms a 1+ cation, and a Group 2 alkaline earth metal forms a 2+ cation.

Calcium shows this pattern clearly. A neutral calcium atom has 20 protons and 20 electrons. It can lose two electrons to form Ca2+, which has 20 protons, 18 electrons, and a 2+ charge. This ion has the same number of electrons as argon. The name of the metal ion is the same as the metal atom, so Ca2+ is called a calcium ion.

Nonmetals on the far right usually gain electrons to reach the electron count of the next noble gas. Their anion charge often matches how many groups they are away from the noble gases. Group 17 elements usually gain one electron to form 1− anions, and Group 16 elements usually gain two electrons to form 2− anions.

Bromine is one example. A neutral bromine atom has 35 protons and 35 electrons. It can gain one electron to form Br− with 35 protons, 36 electrons, and a 1− charge. This ion has the same number of electrons as krypton. The trend between group position and ion charge helps in many cases, but it becomes less reliable near the center of the periodic table. Transition metals and some other metals often have variable charges. Copper can form 1+ or 2+ ions, and iron can form 2+ or 3+ ions.

Predicting Ion Charges on the Periodic Table

predicting-ion-charges-on-the-periodic-table

the atomic theory of matter

Dalton’s Laws and Early Atomic Ideas

Dalton’s atomic theory explains matter with atoms, elements, and compounds. It also shows how chemical changes follow simple laws. This idea gave chemistry a microscopic model for what can be seen in the lab. The earliest recorded ideas about matter came from ancient Greek philosophers. Leucippus and Democritus said all matter was made of tiny, finite particles called atomos, meaning “indivisible.” Aristotle and others later argued that matter was made from four elements: fire, earth, air, and...

subatomic particles

Atomic Structure: Protons, Neutrons, and Electrons

Atomic structure is built from three subatomic particles: protons, neutrons, and electrons. Atoms make up all matter, and these particles explain an atom’s mass and charge. The electron was first identified at the end of the 19th century by J.J. Thomson. He used a cathode ray tube, a sealed glass tube with almost all the air removed and two metal electrodes. When high voltage was applied, a visible beam called a cathode ray formed. The beam bent toward positive charge and away from negative...

elements: chemical symbols and isotopes

Reading Element Symbols and Isotope Notation

Chemical symbols and isotope notation help identify elements and their atoms. A chemical symbol is an abbreviation for an element or a single atom of that element. Mercury, for example, is written as Hg. The same symbol can point to one atom in the microscopic domain or to many atoms of the element in a container or sample. Many symbols come from the element’s common English name. Others come from Latin, Greek, or German names. Aluminum uses Al, while iron uses Fe from the Latin word Ferrum.

ions and ionic charges

Ion charges can often be predicted from an element’s position on the periodic table. In chemical reactions, the nucleus stays unchanged, but electrons may be transferred, lost, or shared. When atoms gain or lose electrons during compound formation, they become ions, which are electrically charged particles. A positive ion is called a cation. A cation has more protons than electrons because it lost electrons. A negative ion is called an anion. An anion has more electrons than protons because it...

the periodic table

Periodic Table Patterns and Element Groups

The periodic table organizes elements by repeating patterns in their properties. Chemists first noticed that some elements behaved alike, so they grouped them by chemical behavior. Lithium, sodium, and potassium are one example. They are shiny and conduct heat and electricity well. Calcium, strontium, and barium form another group with similar physical and chemical properties. Yet these two groups are not the same. The lithium group is much more reactive, and its elements form oxygen compounds...

atomic mass

Average Atomic Mass and Isotopes

Average atomic mass explains why many elements on the periodic table have decimal values. Atoms are extremely small, so scientists use the atomic mass unit, or amu, to measure them. A carbon atom weighs less than 2 × 10−23 g, and the amu is defined from carbon-12. One amu is exactly 1/12 the mass of one carbon-12 atom, which is 1.6605 × 10−24 g. The dalton (Da) and the unified atomic mass unit (u) mean the same thing as the amu. For a single atom, atomic mass is usually close to its mass...

molar mass

Mole, Mass, and Avogadro’s Number

The mole links mass and the number of particles in a substance. It gives chemists a standard way to count atoms and molecules in samples that are far too small to see. It also helps show why substances with the same kinds of atoms can still have very different properties, like water, H2O, and hydrogen peroxide, H2O2. The mole is an amount unit, like a pair or a dozen. One mole contains 6.02214076 × 10^23 discrete entities, such as atoms or molecules. This number is usually rounded to 6.022 ×...

key terms and concepts

Learn how the periodic table helps predict cation and anion charges, with examples like calcium, bromine, copper, and iron for grades 9–12.

Predicting Ion Charges on the Periodic Table | JoVE K12

chemistry

JoVE Core: Chimica illustra concetti chiave di chimica attraverso video animazioni concise e di immediata comprensione. Inoltre, i video della sezione "scienziati in azione" mostrano procedure metodologiche realizzate da ricercatori provenienti dai migliori laboratori internazionali.

Louisiana Student Standards for Science

High School

Matter And Its Interactions

HS-PS1-1

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

Matter and Its Interactions

CHEM1.PS1.13

Virginia  Standards of Learning

HIgh School

CH.2

CH.2.a

PS.4

PS.4.a

Arizona Science Standards

HS+C.P1

HS+C.P1U1.1

HS.P1

HS.P1U1.2

Alabama Course of Study Science

9-12.C.1.1.a

9-12.C.1.1.b

9-12.PS.3.4

9-12.PS.3.4.d

Florida Department of Education

SC.912.P.8

SC.912.P.8.4

Texas Essential Knowledge and Skills

Chemistry and Physics

IPC.7

IPC.7.A

Georgia Standards of Excellence

SPS1.

Properties of Atoms, Ions, and Isotopes

Classifying Matter by State

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Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

Elements: Chemical Symbols and Isotopes

A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is ...

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

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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 ...

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Molecular Comparison of Gases, Liquids, and Solids

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Intermolecular vs Intramolecular Forces

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Intermolecular Forces

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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 ...

The Bohr Model

Following the work of Ernest Rutherford and his colleagues in the early twentieth century, the picture of atoms consisting of tiny dense nuclei surrounded ...

Emission Spectra

When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a ...

The de Broglie Wavelength

In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a ...

The Uncertainty Principle

Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that ...

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

PS.PSc.1.4

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

Use models to compare representations of atoms, ions, and isotopes.

The Periodic Table

As early chemists discovered more elements, they realized that various elements could be grouped by their similar chemical behaviors. One such grouping ...

Periodic Classification of the Elements

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atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

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Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Alkali Metals

Group 1 elements are soft and shiny metallic solids. They are malleable, ductile, and good conductors of heat and electricity. The melting points of the ...

Halogens

Group 17 elements, known as halogens, are nonmetals. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine a solid. ...

Noble Gases


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Use the Periodic Table as a model to predict the relative properties (metallic/nonmetallic character, ionic charge, and reactivity) and arrangement of elements based on the pattern of valence electrons in the outermost energy levels of atoms.

PS.PSc.1.6

Types of Chemical Bonds

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Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Bonding in Metals

Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Dr&#xFC;de called the ...

Construct an explanation to classify the type of chemical bond that occurs (covalent, ionic, or metallic) in a given substance.

PS.PSc.2.1

Nomenclature of Alkanes

In the late 19th-century, the number of new chemical compounds discovered increased tremendously. Hence, the necessity arose to develop a naming system ...

Nomenclature of Alkenes

The IUPAC naming system for alkenes replaces -an- with -en- in the corresponding parent alkanes. Accordingly, a simple alkene replaces the -ane suffix of ...

Nomenclature of Alkynes

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Structure and Nomenclature of Alcohols and Phenols

Overview 
Alcohols are one of the most important functional groups in organic chemistry. The name of alcohol comes from the hydrocarbon from which it is ...

Structure and Nomenclature of Ethers

Structure and Bonding
Ethers are organic compounds with an ether functional group which is characterized by an oxygen atom connected to two &#8212; ...

IUPAC Nomenclature of Aldehydes

Aldehydes are named based on the systematic nomenclature rules set by the IUPAC. For acyclic aldehydes, the longest carbon chain containing the aldehydic ...

Use models to apply International Union of Pure and Applied Chemistry (IUPAC) conventions to name and write formulas for simple compounds.

PS.PSc.2.2

Understand types, properties, and structure of matter.

Predicting Ion Charges on the Periodic Table

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