Name: how ionic charge changes ion size
Uploaded: 2020-09-03T13:38:28.000Z
Duration: 3 min 10 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

Chemistry

Matter and its Interactions

PS.Chm.2.2

Ionic Radii

Un radio iónico es el radio de un catión o un anión definido por la distancia entre iones en un compuesto iónico. Los cationes son más pequeños que el átomo principal, mientras que los aniones son más grandes. Al igual que los radios atómicos, los radios iónicos están determinados por el número de electrones, los orbitales que contienen sus electrones de valencia, y la carga nuclear.Considere el litio, que tiene una configuración de un núcleo de helio y un electrón 2s más externo. El electrón 2s está protegido de la carga nuclear por dos electrones 1s y contribuye al radio atómico de 152 picómetros. La pérdida del electrón 2s más externo genera un catión de litio, que tiene menos electrones, pero el mismo número de protones que el átomo progenitor.Los dos electrones 1s se mantienen más cerca del núcleo. porque experimentan una mayor carga nuclear efectiva que el electrón 2s. Por lo tanto, el radio iónico del catión de litio es de 60 picómetros, que es mucho más pequeño que el átomo principal.Esta tendencia se observa generalmente con todos los cationes metálicos y sus átomos progenitores. Por el contrario, los aniones son más grandes que sus átomos originales. Cuando un átomo de flúor acepta un electrón, hay un electrón más externo adicional, pero el número de protones, y por tanto la carga nuclear, sigue siendo la misma.El aumento de la repulsión de electrones hace que los electrones se extiendan más en el espacio. Por tanto, el anión fluoruro tiene un radio de 136 picómetros, que es mucho más grande que el átomo principal. En general, el radio iónico de los elementos del bloque s y p aumenta hacia abajo, a medida que el número de niveles de la energía principal aumentan y, por tanto, el número de orbitales.Qué ocurre con un grupo de átomos y iones que tienen la misma cantidad de electrones? Se denominan series isoelectrónicas y se pueden organizar aumentando el número atómico. Cada miembro de la serie isoelectrónica representada tiene 18 electrones.Sin embargo, difieren en el número de protones. El ion sulfuro tiene 16 protones que atraen 18 electrones, mientras que el ion calcio tiene 20 protones que atraen el mismo número de electrones. Por lo tanto, con más protones, el calcio puede acercar mucho más a los electrones al núcleo que el sulfuro, dando como resultado el ion calcio que es más pequeño que el ion sulfuro.Cuanto mayor es la carga nuclear, menor es el radio, aunque añadir una capa de electrones interrumpe esta tendencia. Sin embargo, el ion de sulfuro es el más grande y el de calcio es el más pequeño de esta serie.

radio iónico

El radio iónico es la medida utilizada para describir el tamaño de un ión. Un catión siempre tiene menos electrones y el mismo número de protones que el átomo padre; es más pequeño que el átomo del que se deriva. Por ejemplo, el radio covalente de un átomo de aluminio (1s22s22p63s23p1) es 118 pm, mientras que el radio iónico de un Al3+ (1222s22p6) es 68 pm. A medida que los electrones son removidos de la capa de valencia externa, los electrones centrales restantes que ocupan capas más pequeñas experimentan una mayor carga nuclear efectiva Zef y se dibujan aún más cerca del núcleo.
 
 Los cationes con cargas más grandes son más pequeños que los cationes con cargas más pequeñas (por ejemplo, el V2+ tiene un radio iónico de 79 pm, mientras que el de V3+ es 64 pm). Avanzando hacia abajo en los grupos de la tabla periódica, los cationes de elementos sucesivos con la misma carga generalmente tienen radios mayores, correspondientes a un aumento en el número cuántico principal, n.
 
 Un anión (ion negativo) se forma por la adición de uno o más electrones a la capa de valencia de un átomo. Esto resulta en una mayor repulsión entre los electrones y una disminución en la Zef por electrón. Ambos efectos (el mayor número de electrones y la disminución de la Zef) hacen que el radio de un anión sea mayor que el del átomo padre. Por ejemplo, un átomo de azufre ([Ne]3s23p4) tiene un radio covalente de 104 pm, mientras que el radio iónico del anión de sulfuro ([Ne]3s23p6) es de 170 pm. Para elementos consecutivos en sentido descendente presentes en cualquier grupo, los aniones tienen números cuánticos principales más grandes y, por lo tanto, radios más grandes.
 
 Se dice que los átomos e iones que tienen la misma configuración electrónica son isoelectrónicos. Ejemplos de especies isoelectrónicas son N3–, O2–, F–, Ne, Na+, Mg2+ y Al3+ (1s22s22p6). Otra serie isoelectrónica es P3–, S2–, Cl–, Ar, K+, Ca2+ y Sc3+ ([Ne]3s23p6). Para átomos o iones que son isoelectrónicos, el número de protones determina el tamaño. Cuanto mayor sea la carga nuclear, menor será el radio en una serie de iones y átomos isoelectrónicos.
 
 Este texto es adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/6-5-periodic-variations-in-element-properties">OpenStax Química 2e, Sección 6.5: Variaciones periódicas en las propiedades de los elementos.</a>

Radio Iónico

El radio iónico es la medida utilizada para describir el tamaño de un ion. Un catión siempre tiene menos electrones y el mismo número de protones que el átomo padre; eso...

Education

Educación

JoVE Core

Química

Periodic Properties of the Elements

Propiedades periódicas de los elementos

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

how ionic charge changes ion size

Ionic radius describes the size of an ion. It changes when an atom gains or loses electrons. Cations are positive ions with fewer electrons than the parent atom, and they are smaller than the atoms they come from.

Aluminum shows this pattern clearly. A neutral aluminum atom has a covalent radius of 118 pm, while Al3+ has an ionic radius of 68 pm. When electrons are removed from the outer valence shell, the remaining core electrons feel a stronger effective nuclear charge, or Zeff. That pull draws them closer to the nucleus.

Cations with larger charges are usually smaller than cations with smaller charges. For example, V2+ has an ionic radius of 79 pm, while V3+ is smaller at 64 pm. Moving down a group in the periodic table, cations with the same charge generally get larger. This happens because the principal quantum number, n, increases.

Anions are negative ions formed when one or more electrons are added to the valence shell. Extra electrons increase electron repulsion and reduce Zeff per electron. Both effects make an anion larger than its parent atom. Sulfur is an example: a sulfur atom has a covalent radius of 104 pm, while the sulfide anion has an ionic radius of 170 pm. Anions also tend to have larger radii down a group because n increases.

Atoms and ions with the same electron configuration are called isoelectronic. One example set is N3−, O2−, F−, Ne, Na+, Mg2+, and Al3+, which all have the same electron arrangement. Another is P3−, S2−, Cl−, Ar, K+, Ca2+, and Sc3+. In an isoelectronic series, the number of protons controls size. The greater the nuclear charge, the smaller the radius.

How Ionic Charge Changes Ion Size

periodic classification of the elements

How Valence Electrons Shape the Periodic Table

The periodic table organizes elements by increasing atomic number, and it also shows why elements in the same group behave alike. As the electron configurations are placed into the table, a repeating pattern appears in the outer shells of atoms. These outer electrons are called valence electrons, and they play the biggest role in chemical reactions. They are the highest-energy electrons in an atom, so they are easier to lose or share than core electrons. Valence electrons also help determine...

ionization energy

Ionization Energy Trends in the Periodic Table

Ionization energy is the energy needed to remove an electron from a gaseous atom or ion in its ground state. The first ionization energy, or IE1, removes the most loosely bound electron and forms a 1+ cation. The second ionization energy, IE2, removes the next electron, and each later ionization energy removes another electron from the atom or ion. Ionization always requires energy, so these processes are endothermic. That means ionization energy values are always positive. In general, larger...

atomic radii and effective nuclear charge

atomic-radii-and-effective-nuclear-charge

Periodic Trends in Atomic Size

Periodic trends in atomic size help explain why atoms get larger or smaller across the periodic table. Elements in the same group show similar chemical behavior because they have the same number and arrangement of valence electrons. Across a period, each new element adds one proton to the nucleus and one electron to the valence shell. Down a group, the number of valence electrons stays the same, but the principal quantum number increases by one. Atomic radius is not easy to define with perfect...

ionic radii

Ionic radius describes the size of an ion. It changes when an atom gains or loses electrons. Cations are positive ions with fewer electrons than the parent atom, and they are smaller than the atoms they come from. Aluminum shows this pattern clearly. A neutral aluminum atom has a covalent radius of 118 pm, while Al3+ has an ionic radius of 68 pm. When electrons are removed from the outer valence shell, the remaining core electrons feel a stronger effective nuclear charge, or Zeff. That pull...

electron affinity

Electron Affinity Trends on the Periodic Table

Electron affinity is the energy change that happens when a gaseous atom gains an electron and becomes a negative ion, or anion. For many elements, this process releases energy, so the electron affinity value is negative. For some elements, energy must be added instead, so the value is positive. Electron affinity also applies when more than one electron is added. The second electron affinity is the energy change for adding an electron to an anion to make a 2− ion. Later electron affinities...

alkali metals

Alkali Metals: Reactivity Trends

Alkali metals are Group 1 elements with one valence electron. They are soft, shiny metallic solids that are malleable, ductile, and good conductors of heat and electricity. Their melting points are unusually low for metals and drop as you move down the group. Density generally increases down the group, except for potassium. The trend in atomic size helps explain their behavior. Moving from lithium to cesium, each element has a higher principal quantum number, so the outer electron is farther...

halogens

Halogens: Trends and Reactions

Halogens are Group 17 nonmetals that show clear trends in structure and reactivity. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid. Astatine is highly unstable and radioactive, so most of its properties are still unknown because it has a very short half-life. Tennessine is a synthetic element that is also predicted to belong to this group. These elements do not usually exist as single atoms. Instead, they form diatomic molecules, which means...

noble gases

Noble Gases: Sources, Uses, and Reactions

Noble gases are the group 18 elements helium, neon, argon, krypton, xenon, and radon. They were called “noble” because they were once thought to be nonreactive. That idea changed in 1962, when Dr. Neil Bartlett at the University of British Columbia showed that this assumption was not fully correct. These gases occur in very small amounts in the atmosphere. Some natural gas contains 1–2% helium by mass. Helium is separated from natural gas by removing the condensable components, which leaves...

key terms and concepts

Learn how cations and anions change size, why ionic radius varies with charge, and how isoelectronic species compare across the periodic table.

How Ionic Charge Changes Ion Size | JoVE K12

chemistry

JoVE Core Química da vida a los conceptos de química general mediante lecciones de vídeo basadas en animaciones, concisas y fáciles de entender. Además, en los vídeos de científicos en acción, se muestran experimentos de investigación clásicos y originales realizados en laboratorios de todo el mundo.

Physical Science

PS.PSc.1.6

Pennsylvania State Academic Standards

Chemical Reactions

3.2.9-12.C

Structure and Properties of Matter

3.2.9-12.A

Louisiana Student Standards for Science

High School

Matter And Its Interactions

HS-PS1-1

HS-PS1-2

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Periodic trends of the elements

Structure And Properties Of Matter

Periodic Table

Tennessee Academic Standards

Matter and Its Interactions

CHEM1.PS1.12

Virginia  Standards of Learning

HIgh School

CH.2

CH.2.c

PS.2

PS.2.b

PS.4

PS.4.a

PS.4.b

Arizona Science Standards

HS+C.P1

HS+C.P1U1.1

Texas Essential Knowledge and Skills

CHEM.5

CHEM.5.A

CHEM.5.C

CHEM.7

CHEM.7.A

Alabama Course of Study Science

9-12.C.1.1

9-12.C.1.1.e

motion-and-stability-forces-and-interactions

Motion and Stability: Forces and Interactions

9-12.C.2.2.f

9-12.PS.3.4.b

Next Generation Science Standards

Chemistry and Physics

IPC.7

IPC.7.B

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Structure and Properties of Matter

HS-PS1-1.

HS. Chemical Reactions

HS-PS1-2.

Georgia Standards of Excellence

SPS1.

Periodic Table Trends

SC1.

periodic-table-trends-atomic-radii-ionization-and-electronegativity

Periodic Table Trends: Atomic Radii, Ionization, and Electronegativity

Scientific Laws and Theories

Scientific Laws

In science, a law is defined as a concise, verbal or mathematical, statement that summarizes a vast number of experimental observations. ...

The Scientific Method

Chemistry is an empirical science. Scientists often pose questions to understand the chemistry in everyday life and seek answers to these questions. To ...

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

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 ...

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 ...

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 ...

Use models to explain how the scientific understanding of atomic structure has evolved.

PS.Chm.1.1

Radioactivity and Nuclear Equations

Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for ...

Types of Radioactivity

The most common types of radioactivity are &#945; decay, &#946; decay, &#947; decay, neutron emission, and electron capture.
Alpha (&#945;) decay is the ...

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10&#8722;15 meters, a nucleus is ...

Nuclear Binding Energy

The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect ...

Radioactive Decay and Radiometric Dating

Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. ...

Nuclear Fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger ...

Nuclear Power

Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by ...

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process ...

Nuclear Transmutation

Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with ...

Use models to compare nuclear reactions including alpha decay, beta decay and gamma decay; nuclear fusion and nuclear fission.

PS.Chm.1.2

Atomic Orbitals

An atomic orbital represents the three-dimensional regions in an atom where an electron has the highest probability to reside. The radial distribution ...

The Pauli Exclusion Principle

The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that ...

The Energies of Atomic Orbitals

In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are ...

The Aufbau Principle and Hund's Rule

To determine the electron configuration for any particular atom, we can build the structures in the order of atomic numbers. Beginning with hydrogen, and ...

electron-configuration-of-multielectron-atoms

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 ...

Use models to explain how electrons are distributed in atoms.

PS.Chm.1.3

Periodic Classification of the Elements

The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their ...

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 ...

Atomic Mass

Atoms &mdash; and the protons, neutrons, and electrons that compose them &mdash; are extremely small. For example, a carbon atom weighs less than 2 ...

Molar Mass

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, ...

Use the Periodic Table as a model to predict the relative properties of elements based on the pattern of valence electrons in the outermost energy levels of atoms.

PS.Chm.2.1

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 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

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

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 ...

Construct an explanation to infer the atomic size, reactivity, electronegativity, and ionization energy of an element based on its position in the Periodic Table.

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Lewis Symbols and the Octet Rule

Chemical bonds are complex interactions between two or more atoms or ions, which reduce the potential energy of the molecule. Gilbert N. Lewis developed a ...

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 ...

The Born-Haber Cycle

Lattice Energy&#xA0;

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a ...

trends-in-lattice-energy-ion-size-and-charge

Trends in Lattice Energy: Ion Size and Charge

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

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 ...

Electronegativity

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity.&#xA0;

Electronegativity values of ...

bond-polarity-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Analyze and interpret data to explain the mechanisms and properties of the two main types of intramolecular (ionic and covalent) bonds.

PS.Chm.3.1

Analyze the structure of atoms and isotopes.

How Ionic Charge Changes Ion Size

Description

Transcript

Tags

More videos by Standards