Name: atomic elements, molecules, and bonds
Uploaded: 2020-09-03T13:38:25.000Z
Duration: 2 min 38 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.3.3

Molecules and Compounds

在大自然中，万物是由基本的化学单位组成，他们被称为元素，每个元素拥有个别特别的物 理或化学属性。週期表列出至今被辨别出的元素 共118个。元素的组成因子是原子。有些元素，比如氦，氖，银或铂以独立的原子存在于世上。其他元素，比如氢，氧，或硫，他们都以两个或更多的原子组成而存在于世上。这些原子被一个 强静电力绑在一起，被称为化学键，以形成稳固的单位，为分子，比如水及果糖。这些被两种或多种原子以 固定的化学比例所组成的分子，也叫做化合物。因此，水和果汤都是化合物。水是由两个原子的氢及一 原子的氧组成的分子。相对的，果糖为被六个碳原子，十二个氢原子及六个氧原子所组成的分子。在化合物下各个原子 由化学键连接在一起，从而决定了所形成的化合 物的类型（例如分子或离子化合物）当非金属原子聚集且透过共价 键分享他们的电子时，便会产出共价分子化合物，比如水。与单个原子相比，两个原子之间共享的电子降低 势能并创建了更稳定的分子。当金属和非金属原子结合在一起时，就会形成离子化合物，如氯化钠。金属元素容易失去电子成为阳离子，而非金属元素容易得到电子成为阴离子。因此当金属原子转换电子至非金属原子，带相反电荷的离子之间 的静电相互作用形成离子键。元素变成化合物的能 力导致自然中 存在着多样化的物质。

分子和化合物

<h4>原子和分子</ h4>
 
 宇宙中的一切都是由物质组成的，物质是由元素的组合组成的。原子是元素的最小单元，保留元素的所有属性。例如，一枚银币是由银原子组成的，每个银原子都保留了元素的独特属性＆mdash;银。
 
 元素是由相同原子组成的纯物质，无法通过化学变化将其分解为较简单的物质。原子元素包含单个原子作为其基本单元。碳由碳原子组成，钠由钠原子组成。大多数元素是原子元素。但是，有一些元素以原子的组合形式存在，而在自然界中从未以单个原子的形式被发现过。这些被称为分子元素。分子元素以两个或多个原子键合在一起的分子形式存在。它们可以是双原子的，例如氢气（H 2 ），氧气（O 2 ）或氯气（Cl 2 ）或多原子的，例如硫（S 8 ）和磷（P 4 ）。
 
 一个分子由两个或两个以上的原子组成，这些原子通过称为化学键的强力连接。一个分子可以由两个或多个相同的原子组成，或者可以由两个或多个不同的原子组成。当该分子由两个或多个不同元素组成的原子组成时，它们以固定的整数比率组合，该分子也是化合物。例如，水是化合物，每个水分子（H 2 O）是包含两个氢原子和一个氧原子的单元。葡萄糖分子（C 6 H 12 O 6 ）也是一个包含六个碳原子，十二个氢原子和六个氧原子的化合物 。
 
 化合物是由固定的确定比例的两种或更多种元素组成的纯净物质。根据存在的键，化合物被分类为分子或离子。
 
 <h4>化合物</ h4>
 
 将原子保持在化合物内的吸引力的性质决定了形成的化学键的类型。电子在金属原子和非金属原子之间的完全转移导致形成带相反电荷的离子。离子之间的静电吸引称为离子键，通过离子键形成的化合物为离子化合物。例如，氯化钠NaCl是一种离子化合物。
 
 两个或多个非金属原子之间的电子共享导致共价键，通过共价键形成的化合物称为共价或分子化合物。共价键是键合原子带正电的原子核与原子间共享的带负电的电子之间的吸引力。
 
 本文改编自<a href="https://openstax.org/books/chemistry-2e/pages/2-6-molecular-and-ionic-compounds"> OpenStax 化学 2e，第2节2.6：分子和离子化合物。</a>

原子和分子

宇宙中的一切都是由物质组成的，而物质又是由多种元素的组合组成的。原子是 ...

Education

教育

JoVE Core

化学

Molecules, Compounds, and Chemical Equations

分子、化合物与化学方程式

molecules-compounds-and-chemical-equations

KEY TERMS AND CONCEPTS

关键术语与概念

atomic elements, molecules, and bonds

Matter is made of elements, and elements are built from atoms. An atom is the smallest unit of an element that still keeps that element’s properties. A silver coin, for example, is made of silver atoms. Each atom keeps the unique properties of silver.

Elements are pure substances made of identical atoms. They cannot be broken down into simpler substances by chemical changes. Most elements are atomic elements, which use single atoms as their basic unit. Carbon and sodium are examples of atomic elements.

Some elements do not occur as single atoms in nature. These are called molecular elements. They exist as molecules made of two or more bonded atoms. Some are diatomic, such as hydrogen (H2), oxygen (O2), and chlorine (Cl2). Others are polyatomic, such as sulfur (S8) and phosphorous (P4).

A molecule is a group of two or more atoms joined by strong chemical bonds. The atoms in a molecule may be the same, or they may be different. When a molecule contains atoms from two or more different elements in fixed whole number ratios, it is also a compound. Water is a compound, and each H2O molecule has two hydrogen atoms and one oxygen atom. Glucose (C6H12O6) is another compound, with six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.

Compounds are pure substances made of two or more elements in fixed, definite proportions. They are classified as molecular or ionic based on the bonds they contain. The kind of attraction between atoms determines the bond type. When electrons transfer completely from a metal atom to a nonmetal atom, oppositely charged ions form. The electrostatic attraction between those ions is an ionic bond, and the result is an ionic compound such as sodium chloride (NaCl). When two or more nonmetal atoms share electrons, they form covalent bonds. Compounds formed this way are covalent, or molecular, compounds.

Atomic Elements, Molecules, and Bonds

molecules and compounds

Matter is made of elements, and elements are built from atoms. An atom is the smallest unit of an element that still keeps that element’s properties. A silver coin, for example, is made of silver atoms. Each atom keeps the unique properties of silver. Elements are pure substances made of identical atoms. They cannot be broken down into simpler substances by chemical changes. Most elements are atomic elements, which use single atoms as their basic unit. Carbon and sodium are examples of atomic...

molecular models

Molecular Model Types in Chemistry

Molecular models help chemists and students visualize the structures and shapes of atoms and molecules. They represent the molecular architecture of chemical compounds in a way that is easier to study than formulas alone. Skeletal models are simple two-dimensional drawings of compounds. They show the molecular framework, or the bonds, without drawing every atom. In this model, many carbon and hydrogen atoms are not shown directly. Their positions are implied by the ends and junctions of the...

organic compounds

Organic Molecules in Everyday Chemistry

Organic molecules are carbon-based compounds found in living things and in many everyday products. Most organic compounds have carbon as the main element, bonded to hydrogen and other carbon atoms. Some carbon-containing substances, such as carbonates, cyanides, and simple oxides like CO and CO2, are not classified as organic. Carbon can form up to four strong bonds, which helps explain why organic compounds can make chains and rings of many sizes and shapes. These molecules appear in...

formula mass and mole concepts of compounds

formula-mass-and-mole-concepts-of-compounds

Chemical Formula Mass and Percent Composition

Chemical formula mass and percent composition help describe the makeup of compounds. A chemical formula shows which atoms are present and how many of each atom appear in a substance. For covalent compounds, the formula shows the atoms in one molecule. That is why formula mass can also be called molecular mass. Chloroform, CHCl3, is one example. Its formula shows one carbon atom, one hydrogen atom, and three chlorine atoms. The molecular mass is the sum of their average atomic masses. Ionic...

experimental determination of chemical formula

experimental-determination-of-chemical-formula

Finding Empirical and Molecular Formulas

Chemical formulas show the elemental makeup of a compound. When a formula is unknown, scientists often start by measuring the masses of the elements in the sample. Those mass data are then used to find the simplest whole-number ratio of atoms, which gives the empirical formula. To get from mass to atom ratio, the masses of the elements are first converted to moles using molar masses. Chemical formulas describe numbers of atoms, not masses, so this step is necessary. In one example, 1.71 grams...

chemical equations

Reading Chemical Equations and Balancing Them

Chemical equations show the identities and relative amounts of substances in a chemical reaction. The substances that react are called reactants, and their formulas are written on the left side of the equation. The substances formed are called products, and their formulas are written on the right side. A plus sign (+) separates formulas on the same side, and an arrow (→) shows the change from reactants to products. The numbers in a chemical equation are shown with coefficients. A coefficient...

key terms and concepts

Learn how atoms form elements, molecules, and compounds, and compare ionic and covalent bonds using examples like water, glucose, and sodium chloride.

Atomic Elements, Molecules, and Bonds | JoVE K12

chemistry

JoVE Core 化学通过简单明了且通俗易懂的动画视频课程，将普通化学概念带入到现实生活当中。此外，在科学家行动视频中，我们演示了在实验室中进行的经典和原始研究实验。

PS.Chm.4.3

Physical Science

PS.PSc.1.1

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Classification of matter

Virginia  Standards of Learning

HIgh School

CH.3

CH.3.a

Alabama Course of Study Science

Matter and Its Interactions

9-12.PS.3.4.c

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

High School

C-PS1-3.

motion-and-stability-forces-and-interactions

Motion and Stability: Forces and Interactions

C-PS2-6.

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

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

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.

PS.Chm.2.2

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 ...

Resonance

The Lewis structure of a nitrite anion (NO2&minus;) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O ...

Formal Charges

In some cases, there are seemingly more than one valid Lewis structures for molecules and polyatomic ions. The concept of formal charges can be used to ...

Exceptions to the Octet Rule

Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:


	...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

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

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

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, ...

surface-tension-capillary-action-and-viscosity

Surface Tension, Capillary Action, and Viscosity

Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded ...

Hydrogen Bonds

Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, ...

Van der Waals Interactions

Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions ...

Construct an explanation to summarize the influences intermolecular forces have on the properties of chemical compounds.

PS.Chm.3.2

Atoms and Molecules

Everything in the universe is made up of matter, and matter is composed of a combination of elements. An atom is the smallest unit of ...

Chemical Formulas

A chemical formula presents information about the proportions of atoms constituting a particular chemical compound or molecule, mainly using symbols of ...

Molecular Models

Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models ...

Classification of Elements and Compounds

Pure substances consist of only one type of matter. A pure substance can be an element or a compound. An element consists of only one type of atom, while ...

ionic-compounds-formulas-and-nomenclature

Ionic Compounds: Formulas and Nomenclature

An element composed of atoms that readily lose electrons (a metal) can react with an element composed of atoms that readily gain electrons (a nonmetal) to ...

molecular-compounds-formulas-and-nomenclature

Molecular Compounds: Formulas and Nomenclature

Molecular compounds or covalent compounds result when atoms share electrons to form covalent bonds. Since there is no electron transfer, molecular ...

Use models to predict chemical names and formulas including ionic (binary & ternary), acidic, and binary covalent compounds.

Analyze the structure of atoms and isotopes.

Atomic Elements, Molecules, and Bonds

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