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

イオン半径とは イオン化合物の イオン間の距離で定義される 陽イオンまたは陰イオンの 半径のことです 陽イオンは 親原子よりも小さく 陰イオンは大きくなります イオン半径は 原子半径と同様に 電子の数 価電子を 保持する軌道 核電荷によって 決まります リチウムを考えてみましょう リチウムは ヘリウム原子核と一番外側の 2s電子の電子配置をしています 2s電子は 2個の1s電子によって 核電荷から遮蔽されており 原子半径152ピコメートルに 貢献しています 一番外側の 2s電子がなくなると 電子数は少ないが 親原子と同じ数の陽子を持つ リチウム陽イオンが 生成されます 2つの1s電子は 2s電子よりも大きな 実効核電荷を持つため 原子核の近くに保持されています このように リチウムカチオンのイオン半径は 60ピコメートルで親原子より はるかに小さくなっています この傾向は すべての 金属陽イオンとその親原子で 一般的に観察されます 対照的に アニオンは 親原子よりも大きい フッ素原子が電子を 受け入れるときには 一番外側の電子が追加されますが 陽子の数 したがって核電荷は 同じままです 電子同士の反発が増えると 電子は 空間に広がっていきます このように フッ化物アニオンは 親原子よりもはるかに大きい 136ピコメートルの半径です 一般的に sとpブロック元素の イオン半径は 主エネルギー準位の数つまり 軌道の数が増加するにつれて 列の下に向かって大きくなります 同じ数の電子を持つ 原子とイオンのグループは どうでしょうか？これらは等電子系列と呼ばれ 原子番号の増加によって 配置することができます 等電子系のメンバーは それぞれ18個の 電子を持っています しかし 陽子の数が違います 硫化物イオンは16個の陽子が 18個の電子を引き寄せており カルシウムイオンは 同じ数の電子を引き寄せる 20個の陽子を持っています このように カルシウムイオンは 硫化物イオンより陽子が多い分 電子を核に近づけることができ 結果としてカルシウムイオンは 硫化物イオンよりも 小さくなります 核電荷が大きいほど 半径は小さくなりますが 電子殻を加えると この傾向は崩れます それにもかかわらずこの系列では 硫化物が最も大きく カルシウムが最も 小さいイオンとなっています

イオン半径

イオン半径とは、イオンの大きさを表すための尺度です。カチオンは常に親原子よりも少ない電子と同じ数の陽子を持っており、元の原子よりも小さいです。 たとえば、アルミニウム原子（ 1s22s22p63s23p1 ）の共有結合半径は 118 pm で、 3+ （ 1s22s22p6）のイオン半径は 68 pm です。 外側の原子価殻から電子が除去されると、より小さい殻を占有する残りの内殻電子の方がより効果的な核電荷Zeffを持ち、原子核の近くに描画されます。 
 
 大きな電荷を持つカチオンは、小さな電荷を持つカチオンよりも小さい（例えば、V2+のイオン半径は79pmであるのに対し、V3+のイオン半径は64pmである）。周期表の族を下っていくと、同じ電荷を持つ連続した元素の陽イオンは一般的に大きな半径を持ち、これは主量子数nの増加に対応しています。 
 
 陰イオン（負イオン）は、原子価殻に 1 つ以上の電子を加えることで形成されます。 これにより、電子間の反発が大きくなり、電子あたりの Zeff が減少します。 どちらの効果も（電子の数が増加し、 Zeff が減少）、陰イオンの半径が親原子の半径より大きくなります。 例えば、硫黄原子（ [Ne] 3s23p4 ）の共有結合半径は 104 pm で、硫化陰イオン（ [Ne] 3s23p6 ）のイオン半径は 170 pm です。 任意の族に続く連続した元素については、陰イオンの主要量子数値が大きくなり、その結果、半径が大きくなります。 
 
 電子構成が同じ原子およびイオンは、等電子と呼ばれます。 等電子種の例としては、 N3–、 O2–、 F–、 Ne、 Na+、 Mg2+、 Al3+ (1s22s22p6)があります。 もう 1 つの等電子族は、 P3–、 S2–、 Cl–、 Ar、 K+、 Ca2+、 Sc3+ ([Ne]3s23p6)です。 等電性の原子またはイオンの場合、陽子の数によってサイズが決まります。 原子電荷が大きいほど、一連の等電イオンと原子の半径が小さくなります。 
 
 このテキストは <a href="https://openstax.org/books/chemistry-2e/pages/6-5-periodic-variations-in-element-properties">、 OpenStax Chemistry 2e の第 6.5 章「元素特性の周期的な変化」に基づいています。</a>

イオン半径は、イオンのサイズを表すために使用される尺度です。カチオンは常に親原子と同じ数の電子と同じ数の陽子を持っています。それ。。。

Education

JoVE Core

化学

Periodic Properties of the Elements

元素の周期的な性質

KEY TERMS AND CONCEPTS

主要用語と概念

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 化学は、簡潔で理解しやすいアニメーションビデオレッスンを使用して、一般的な化学の概念を生き生きとしたものにします。さらに、活動する科学者のビデオでは、現在世界中の実験室で行われている古典的そして独創的な研究・実験をお見せします。

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.

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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 ...

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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

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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

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