Name: electron shells and discovery
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 9 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Chemistry

Matter And Its Interactions

HS-PS1-1

Electron Behavior

전자는 양전하를 띤 핵 주위의 전자 구름에 존재하는 작은 음전하를 띤 입자입니다. 구름 내에서 전자는 껍질 또는 에너지 준위라고 하는 별개의 영역에 있습니다.
에너지 준위는 단순화된 보어(Bohr) 또는 행성 모델(planetary model)을 사용하여 시각화되는 경우가 많으며, 실제로는 복잡한 모양을 가지고 있지만 핵 주위의 고리로 표현됩니다.
이 껍질의 전자는 핵에서 멀어질수록 에너지가 증가합니다.
첫 번째 에너지 준위에는 최대 두 개의 전자가 있을 수 있습니다. 두 번째 쉘은 최대 8개의 전자를 보유할 수 있습니다. 원자 내의 추가 전자는 점점 더 높은 에너지 준위를 채웁니다.
가장 바깥쪽에 있는 껍질에 있는 전자는 원자가 전자라고 하며 원소의 화학적 특성을 결정합니다.
원자가 전자는 원자 간에 공유되어 공유 결합을 형성하거나 이온 결합을 형성하기 위해 전달될 수 있습니다.

전자 행동

전자는 양전하를 띤 원자핵에 끌려 그 주위를 공전하는 음전하를 띤 아원자 입자입니다. 전자는 껍질이라고 하는 에너지 준위와 관련된 공간에 존재하며, 각 껍질 내에서는 하위 껍질과 궤도로 더 세분화됩니다. 전자가 핵 주위를 공전합니다 전자는 핵 외부의 특정 위치에서 발견됩니다. 전자가 존재하는 껍질은 전자의 일반적인 에너지 준위를 나타냅니다. 즉, 핵에 가까울수록 에너지가 적고, 핵에 더 가까울수록 더 많은 에너지를 갖습니다. 부껍질-서브쉘은 전자의 위치와 에너지 준위를 보다 정확하게 나타내며, 궤도는 전자가 핵 주위를 공전하는 확률 영역의 모양을 나타냅니다. 핵에 가장 가까운 전자는 가장 적은 양의 에너지를 가지며, 핵으로부터의 거리가 멀어질수록 전자가 운반하는 에너지의 양도 늘어납니다. 핵에서 멀어질수록 전자가 궤도를 돌 수 있는 공간이 더 많아 외부 껍질이 내부 껍질보다 더 많은 전자를 수용할 수 있습니다. 원자의 가장 바깥쪽 전자는 원자가 껍질에 존재하며 원자가 전자라고 합니다. 이러한 전자는 다른 원자와 이온 및 공유 결합을 형성할 수 있습니다. 전자 발견 1890년대 후반에 J. J. 톰슨(J. J. Thomson)은 음극선관을 사용하여 일련의 실험을 수행하여 최초의 아원자 입자인 전자를 발견했습니다. 음극선관은 전기를 공급하는 전원에 연결된 두 개의 전극이 있는 유리관입니다. 진공은 튜브 내부에서 대부분의 공기를 제거합니다. 전극에 전압이 가해지면 입자 빔이 음전하를 띤 음극에서 양전하를 띤 전극 양극으로 이동합니다. 양극에는 광선이 통과할 수 있도록 작은 구멍이 있습니다. 음극선이 닿으면 튜브 반대쪽 끝의 인 코팅이 빛납니다. 톰슨은 양전하를 띠는 금속판과 음전하를 띠는 금속판 사이에 음극선을 비추고, 관의 맨 끝에서 광선의 위치를 측정했습니다. 광선이 두 판 사이를 통과할 때 음전하 판에서 멀어지면서 양전하 판 방향으로 구부러졌습니다. 같은 전하는 밀어내고 반대 전하는 끌어당기므로 이는 음극선의 입자가 음전하를 띤다는 것을 나타냅니다. 음극 입자의 질량 대 전하 비율을 계산하기 위한 추가 실험에서는 각각의 음전하를 띤 입자의 질량이 알려진 원자 질량의 약 1/2000이라는 사실이 밝혀졌습니다. 이 때문에 톰슨은 어떤 주어진 원자에도 많은 전자가 존재해야 한다는 결론을 내렸습니다. 나중에 양성자와 중성자의 발견으로 원자의 질량 분포와 전체 중성 전하가 설명되었습니다.

이 문서는<a href="https://openstax.org/books/chemistry-2e/pages/6-3-development-of-quantum-theory#0">Openstax, Chemistry 2e, Section 6.3: Development of quantum theory</a>.

전자는 음전하를 띤 아원자 입자로, 양전하를 띤 원자핵에 끌려 그 주위를 공전합니다. 그들은 공간에 거주합니다 ...

Education

교육

JoVE Core

Anatomy and Physiology

해부학 및 생리학

Unit 1

제1단원

Fundamentals of Chemistry

화학의 기초

KEY TERMS AND CONCEPTS

주요 용어 및 개념

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 an electron’s location and energy more precisely. Orbitals describe the shape of an area of probability where an electron may move around the nucleus. The outermost electrons are found in the valence shell and are called valence electrons. These electrons can form ionic and covalent bonds with other atoms.

J. J. Thomson discovered the electron in the late 1890s through experiments with cathode ray tubes. A cathode ray tube is a glass tube with two electrodes, a power source, and a vacuum that removes most of the air. When voltage is applied, a beam of particles travels from the negatively charged cathode to the positively charged anode, and a phosphorus coating glows when the beam strikes it.

Thomson also sent the cathode ray between two metal plates, one positive and one negative. The ray bent away from the negatively charged plate and toward the positively charged plate. This showed that the particles carried a negative charge, since like charges repel and opposite charges attract.

Further experiments showed that each particle had a mass about 1/2000 of the mass of any known atom. Thomson concluded that atoms must contain many electrons. Later, the discovery of protons and neutrons helped explain how an atom’s mass is spread out and why its overall charge is neutral.

Electron Shells and Discovery

what is matter?

Matter, Mass, and Weight Basics

Matter is the substance that makes up the universe, from a grain of sand to a star. Scientists define matter as anything that occupies space and has mass. Mass is the amount of matter in an object, while weight depends on gravity. Mass stays the same whether an object is on Earth or in the zero-gravity environment of outer space. Weight changes when gravity changes. An object weighs more where gravity is stronger and less where gravity is weaker. A piece of cheese that weighs a pound on Earth...

the periodic table and organismal elements

the-periodic-table-and-organismal-elements

Organismal Elements in the Periodic Table

The periodic table helps identify the elements that make up living organisms. Biology groups these as organismal elements because they are the chemical building blocks of life. These elements are found in different amounts in the body. Some are present in large quantities, while others are needed only in small amounts. The video connects the periodic table to the elements that organisms actually use. Understanding organismal elements helps students link chemistry to biology. It shows how...

atomic structure

From Atomos to the Modern Atom

Atoms are the tiny building blocks of matter, and ideas about them go back to the Greek philosopher Democritus. He suggested that everything on Earth is made of atomos, a Greek word meaning "indivisible." That idea later led to the modern word atom. In the 19th century, John Dalton developed an atomic theory that is still largely correct today. He proposed five key ideas. All matter is made of tiny particles called atoms. Atoms of the same element are alike, and atoms of different elements are...

chemical symbols

Chemical Symbols and Element Names

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

Atomic Identity, Mass, and Isotopes

Atomic identity depends on the number of protons in the nucleus, and mass depends on protons and neutrons together. The number of protons is the atomic number, or Z. It defines the element. For example, any atom with six protons is carbon, no matter how many neutrons or electrons it has. In a neutral atom, the number of protons equals the number of electrons. Because of that, the atomic number also tells you the number of electrons in the atom. The total number of protons and neutrons is...

atomic weight

Atomic Mass and Mole Calculations

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

Radioisotopes in Medicine and Imaging

Radioisotopes are unstable isotopes that can be used to study the body and treat disease. An isotope is an atom of the same element that has a different mass because it contains a different number of neutrons. It still has the same number of protons, so it remains chemically identical. English chemist Frederick Soddy explained this idea in the early 1900s and later received the Nobel Prize in Chemistry in 1921. Some isotopes have more neutrons than usual and are called heavy isotopes. These...

electron behavior

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

Ionic bonds form when atoms transfer electrons and become charged particles. A positive ion and a negative ion attract each other because opposite charges pull together. This type of bonding helps explain how some substances are held together. In many cases, an atom loses one or more electrons, while another atom gains them. The atom that loses electrons becomes a cation, which is a positively charged ion. The atom that gains electrons becomes an anion, which is a negatively charged ion. The...

covalent bonds

Polar and Nonpolar Covalent Bonds

Covalent bonds form when atoms share electrons to fill their valence shells. The way those shared electrons are pulled depends on electronegativity, which is an atom's tendency to attract electrons in a bond. That difference also helps explain why some molecules are polar and others are nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds. In these bonds, electrons are shared equally, so there is no charge across the molecule. When two atoms have different...

hydrogen bonds

Hydrogen Bonding and DNA Stability

Hydrogen bonding helps explain why some molecules stick together more strongly than others. A hydrogen bond forms when a weakly positive hydrogen atom, already bonded to an electronegative atom, is attracted to another electronegative atom on a nearby polar molecule. Common examples include water, hydrogen fluoride, and ammonia. This attraction happens because hydrogen has a much lower electronegativity than atoms such as fluorine, oxygen, and nitrogen. The electronegativity difference, along...

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...

states of matter

Solids, Liquids, Gases, and Plasma

Solids, liquids, gases, and plasma are the main forms of matter described here. Solids are rigid and keep a definite shape. Liquids flow and take the shape of their container, although gravity gives the surface a flat or slightly curved top. Solids and liquids also have volumes that stay nearly the same even when pressure changes. Gases behave differently from solids and liquids. A gas takes both the shape and the volume of its container. In matter with this behavior, the particles are far...

colloids and suspensions

Suspensions, Sedimentation, and Colloids

Suspensions and colloids are two common kinds of mixtures seen in everyday life. Mud and water, flour and water, and tempera paint are suspensions. These mixtures are heterogeneous, which means their particles are not spread out evenly. The particles are relatively large and can be seen with the naked eye or a magnifying glass. Suspension particles make mixtures cloudy, and they settle out after mixing. The settling of particles in a suspension is called sedimentation. A blood test can measure...

introduction to chemical reactions

Chemical Reaction Basics and Equilibrium

Chemical reactions start with reactants and end with products. Reactants are the substances that enter a reaction, and products are the new substances that form. For example, sodium and chloride ions are the reactants in the formation of table salt. Chemical reactions follow the law of conservation of mass. Matter is not created or destroyed during the reaction. That means the atoms and elements in the reactants are still present in the products, and nothing new appears in the products that...

types of chemical reactions: anabolic and catabolic

types-of-chemical-reactions-anabolic-and-catabolic

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

types-of-chemical-reactions-exchange-and-reversible

Electron Transfer and Chemical Equilibrium

Exchange reactions and reversible reactions are two important ideas in chemistry. In an exchange reaction, synthesis and decomposition happen at the same time. Chemical bonds are both formed and broken. These reactions can absorb chemical energy, store it, and release it. A special type of exchange reaction is the oxidation-reduction reaction, or redox reaction. In a redox reaction, electrons move from one compound to another. The electrons often come from hydrogen atoms, which contain one...

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

factors-influencing-the-rate-of-chemical-reactions

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

How pH Affects Cells and Digestion

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

Explore how electrons are arranged in shells, subshells, and orbitals, and how J. J. Thomson discovered the electron using cathode ray tubes.

Electron Shells and Discovery | 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.

motion-and-stability-forces-and-interactions

Motion And Stability: Forces And Interactions

HS-PS2-6

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

South Carolina College and Career Ready Science Standards

Physics

Motion and Stability: Forces and Interactions

P-PS2-6.

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

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 And Organismal Elements

Atomic Structure

The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for &#34;indivisible,&#34; from which ...

Electron Configurations

Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest ...

Electronic Structure of Atoms


An atom comprises protons and neutrons, which are contained inside the dense, central&#160;core called the nucleus, with electrons present around the ...

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 ...

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 ...

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 ...

Coulomb's Law

Experiments with electric charges have shown that if two objects each have an electric charge, they exert an electric force on each other. The magnitude ...

Electric Charges

From lightning during thunderstorms to electronic devices, the phenomenon of electromagnetism is all around us. The electromagnetic force is one of the ...

sources-and-properties-of-electric-charge

Sources and Properties of Electric Charge

All objects we see around us consist of atoms, which combine to form molecules. The lightest element in the universe is hydrogen, and a hydrogen atom ...

Types of Forces

In most situations, forces can be grouped into two categories: contact forces and field forces.&#160; Contact forces occur as a result of direct physical ...

Electric Fields

Source: Yong P. Chen, PhD, Department of Physics &#38; Astronomy, College of Science, Purdue University, West Lafayette, IN
An electric field is generated ...

Intermolecular Forces

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

Van der Waals Interactions

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

Chemical Bonds


Atoms participate in a chemical bond formation&#160;to acquire a completed valence-shell electron configuration similar to that of the noble gas nearest ...

Electrons are negatively charged subatomic particles attracted to and orbit around the positively-charged nucleus of an atom. They reside in spaces ...

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 ...

Ions and Ionic Charges

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

Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level and the composition of the nucleus of atoms.  Clarification Statement: Chemistry: Examples of properties that could be predicted from patterns could include reactivity of metals, types of bonds formed, numbers of bonds formed, atomic radius, atomic mass, or reactions with oxygen. Emphasis is on main group elements and qualitative understanding of the relative trends of ionization energy and electronegativity.

Properties of Transition Metals

Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3&#8211;12 are ...

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 ...

Chemical Reactions

A chemical reaction is a process by which the bonds in the atoms of substances are rearranged to generate new substances. Matter cannot be created or ...

Chemical Equations

Chemical equations represent the identities and relative quantities of substances involved in a chemical reaction. The substances undergoing reaction are ...

Introduction to Chemical Reactions

All chemical reactions begin with a reactant, the general term for one or more substances entering the reaction. Sodium and chloride ions, for example, ...

Temperature Dependence on Reaction Rate

The Collision Theory
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. ...

stoichiometry-product-yield-and-limiting-reactants

Stoichiometry, Product Yield, and Limiting Reactants

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Preparation of 25% v/v Ethylenediamine in Deionized WaterExpand
	Here, we show the laboratory ...

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 ...

Dynamic Equilibrium

A reversible chemical reaction represents a chemical process that proceeds in both forward (left to right) and reverse (right to left) directions. When ...

Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.  Clarification Statement: Chemistry: Examples of chemical reactions could include the reaction of sodium and chlorine, carbon and oxygen, or carbon and hydrogen. Reaction classification aids in the prediction of products (e.g. synthesis, decomposition, single displacement, double displacement, and acid-base).

HS-PS1-2

Intermolecular vs Intramolecular Forces

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

comparison-between-electrical-and-gravitational-forces

Comparison Between Electrical And Gravitational Forces

There are four fundamental forces in nature: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. To ...

intermolecular-forces-and-physical-properties

Intermolecular Forces and Physical Properties



Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

electric-field-of-two-equal-and-opposite-charges

Electric Field of Two Equal and Opposite Charges

Atoms generally contain the same number of positively and negatively charged particles, protons, and electrons. Hence, they are electrically neutral. ...

Electric Field

Consider two point charges, each exerting Coulomb force on the other. It is possible to describe the Coulomb interaction via an intermediate step by ...

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 ...

Electric Dipoles and Dipole Moment

Consider two charges of equal magnitude but opposite signs. If they cannot be separated by an external electric field, the system is called a permanent ...

Plan and conduct an investigation to gather evidence to compare the structure of substances at the macroscale to infer the strength of electrical forces between particles.  Clarification Statement: Emphasis is on understanding the strengths of forces between particles, not on naming specific intermolecular forces (such as dipole-dipole). Examples of particles could include ions, atoms, molecules, and network solids (such as graphite). Examples of macro-properties of substances could include the melting point and boiling point, vapor pressure, and surface tension.

HS-PS1-3

bond-dissociation-energy-and-activation-energy

Bond Dissociation Energy and Activation Energy

Bond energy is the energy required to break a bond homolytically. These values are usually expressed in units of kcal/mol or kJ/mol and are referred to as ...

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, ...

Coupled Reactions

Cellular processes such as building and breaking down complex molecules occur through stepwise chemical reactions. Some of these chemical reactions are ...

energy-diagrams-transition-states-and-intermediates

Energy Diagrams, Transition States, and Intermediates

Free-energy diagrams, or reaction coordinate diagrams, are graphs showing the energy changes that occur during a chemical reaction. The reaction ...

What is Metabolism?

Overview

Metabolism represents all of the chemical activity in a cell, including reactions that build molecules (anabolism) and those that break ...

Types of Chemical Reactions: Anabolic and Catabolic

The first law of thermodynamics holds that energy can neither be created nor destroyed&#8212;it can only change form. An organism&#39;s essential function ...

Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.  Clarification Statement: Emphasis is on the idea that a chemical reaction is a system that affects the energy change.  Examples of models could include molecular-level drawings and diagrams of reactions, graphs showing the relative energies of reactants and products, and representations showing energy is conserved.

HS-PS1-4

Electron Shells and Discovery

Description

Transcript

Tags

More videos by Standards