Name: dalton’s laws and early atomic ideas
Uploaded: 2020-09-03T13:38:25.000Z
Duration: 2 min 59 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.1.1

The Atomic Theory of Matter

Os primeiros gregos como Demócrito avançaram pela primeira vez com a ideia dos átomos, a mais pequena unidade indivisível da matéria. Este conceito foi posteriormente apresentado como a Teoria Atômica pelo cientista inglês John Dalton. O primeiro pressuposto da teoria atômica de Dalton sugere que os elementos são compostos por pequenas partículas indivisíveis chamadas átomos.Por exemplo, o hidrogênio é constituído por dois átomos de hidrogênio ligados entre si e o oxigênio é constituído por dois átomos de oxigênio ligados entre si. O segundo pressuposto afirma que embora os átomos do mesmo elemento sejam idênticos, eles diferem dos átomos de outros elementos. Assim, todos os átomos de hidrogênio são idênticos uns aos outros, mas diferem dos átomos de oxigénio.O terceiro pressuposto afirma que átomos de diferentes elementos podem combinar-se uns com os outros, em proporções de números inteiros simples para formar compostos. Por exemplo, dois átomos de hidrogênio e um átomo de oxigênio combinam-se numa proporção de 2 para 1 para formar H2O água. O último pressuposto da teoria de Dalton afirma que as reações químicas não transformam os átomos de um elemento em átomos de um elemento diferente;em vez disso, os átomos existentes reorganizam-se para formar novas substâncias.Durante a formação da água, os átomos de hidrogênio e oxigênio existentes não são criados nem destruídos, apenas reorganizados. Dalton elaborou a sua teoria atômica com base em duas leis anteriores sobre as reações químicas A lei de conservação da massa e a lei das proporções definidas. A lei de conservação da massa estabelece que a massa total antes e depois de uma reação química permanece constante.Assim, 18 gramas de água decompõem-se em 2 gramas de hidrogênio e 16 gramas de oxigênio. A lei das proporções definidas estabelece que independentemente da fonte, num determinado composto químico, a proporção de massa dos elementos constituintes permanece sempre fixa. Assim, uma amostra de água pura terá sempre uma proporção de 1 para 8 de massa de hidrogênio para oxigênio, independentemente da massa total da água.Dalton propôs então a lei das proporções múltiplas com base na sua própria teoria. De acordo com esta lei, quando dois elementos se combinam para formarem mais do que um composto, as diferentes massas de um elemento combinam-se com a massa fixa do outro elemento numa pequena proporção de número inteiro. Assim, uma massa fixa de hidrogênio, 2 gramas, combina-se com diferentes massas de oxigênio, 32 ou 16 gramas, numa pequena proporção de número inteiro de 2 para 1, para formar dois compostos diferentes peróxido de hidrogênio e água.

a teoria atómica da matéria

A primeira discussão gravada sobre a estrutura básica da matéria vem de antigos filósofos Gregos. Leucippus e Democritus argumentaram que toda a matéria era composta por partículas pequenas e finitas que denominavam de atomos, que significa “indivisível”. Mais tarde, Aristóteles e outros chegaram à conclusão de que a matéria consistia em várias combinações dos quatro “elementos” — fogo, terra, ar e água — e poderia ser infinitamente dividida. Curiosamente, estes filósofos pensavam em átomos e “elementos” como conceitos filosóficos, mas aparentemente nunca consideraram realizar experiências para testar as suas ideias. 

A visão Aristotélica da composição da matéria manteve influência por mais de dois mil anos até que o cientista Inglês John Dalton revolucionou a química com a sua hipótese de que o comportamento da matéria poderia ser explicado usando uma teoria atómica. Publicadas pela primeira vez em 1807, muitas das hipóteses de Dalton sobre as características microscópicas da matéria ainda são válidas na teoria atómica moderna. 

Aqui estão os postulados da teoria atómica de Dalton:

<ol>
<li>A matéria é composta por partículas extremamente pequenas chamadas átomos. Um átomo é a menor unidade de um elemento que pode participar de uma mudança química.</li>
<li>Um elemento consiste em apenas um tipo de átomo, que tem uma massa que é característica do elemento e é a mesma para todos os átomos desse elemento. Uma amostra macroscópica de um elemento contém um número incrivelmente grande de átomos, todos com propriedades químicas idênticas.</li>
<li>Os átomos de um elemento diferem nas propriedades dos átomos de todos os outros elementos.</li>
<li>Um composto consiste em átomos de dois ou mais elementos combinados em uma pequena proporção de número inteiro. Em um determinado composto, os números de átomos de cada um dos seus elementos estão sempre presentes na mesma proporção</li>
<li>Os átomos não são criados nem destruídos durante uma alteração química, mas são rearranjados para produzir substâncias diferentes das presentes antes da alteração.</li>
</ol>

Dalton usou três leis de reações químicas como base para a sua teoria: (1) A Lei da Conservação da Massa, (2) A Lei das Proporções Definidas, e (3) A Lei das Proporções Múltiplas. A teoria atómica de Dalton fornece uma explicação microscópica das várias propriedades macroscópicas da matéria. 

A lei da conservação da massa foi descoberta pelo químico Francês, Antoine Lavoisier. Ela afirma que os átomos não são nem criados nem destruídos durante uma alteração química; a massa total de matéria presente quando a matéria muda de um tipo para outro permanece constante.

Dalton também sabia dos experiências do químico Francês Joseph Proust, que demonstrou que todas as amostras de um composto puro contêm os mesmos elementos na mesma proporção por massa. Esta afirmação é conhecida como a lei das proporções definidas ou a lei da composição constante. A sugestão de que o número de átomos dos elementos em um determinado composto existe sempre na mesma proporção é consistente com essas observações. 

Dalton também usou dados de Proust, assim como resultados das suas próprias experiências, para formular outra lei interessante. A lei das proporções múltiplas afirma que quando dois elementos reagem para formar mais de um composto, uma massa fixa de um elemento reagirá com massas dos outros elementos em uma proporção de números pequenos e inteiros. 

A teoria de Dalton forneceu uma estrutura que foi mais tarde expandida para demonstrar que o átomo é composto por partículas subatómicas e que átomos do mesmo elemento podem diferir em massa, conhecidos como isótopos. 

Este texto é adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/2-1-early-ideas-in-atomic-theory">Openstax, Chemistry 2e, Section 2.1: Early Ideas in Atomic Theory.</a>

A Teoria Atómica da Matéria

A primeira discussão registrada sobre a estrutura básica da matéria vem de antigos filósofos gregos. Leucipo e Demócrito argumentaram que toda a matéria ...

Education

JoVE Core

Química

Atoms and Elements

Átomos e Elementos

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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 water. They also believed matter could be divided forever, and these ideas were treated as philosophy rather than experiments.

That view lasted for more than two thousand years. Then English scientist John Dalton changed chemistry with an atomic theory of matter. He first published it in 1807. Many of his ideas still fit modern atomic theory.

Dalton’s postulates describe matter at the atomic level. Matter is made of extremely small particles called atoms. An atom is the smallest unit of an element that can take part in a chemical change. An element contains only one type of atom, and atoms of the same element have the same characteristic mass and chemical properties. Atoms of different elements have different properties. A compound is made of atoms of two or more elements joined in a small, whole-number ratio, and the ratio stays the same in a given compound. During a chemical change, atoms are not created or destroyed. They are rearranged into new substances.

Dalton built his theory using three key laws of chemistry. The law of conservation of mass says mass stays constant during a chemical change, a result linked to Antoine Lavoisier. The law of definite proportions, also called the law of constant composition, says every pure sample of a compound contains the same elements in the same mass ratio, as shown by Joseph Proust. Dalton also used the law of multiple proportions, which says that when two elements form more than one compound, fixed masses of one element combine with the other in small whole-number ratios.

Dalton’s atomic theory gives a microscopic explanation for macroscopic matter. It also helped later scientists show that atoms contain subatomic particles. Later work also showed that atoms of the same element can differ in mass, which are called isotopes.

Dalton’s Laws and Early Atomic Ideas

the atomic theory of matter

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

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...

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

Explore Dalton’s atomic theory, the laws of conservation of mass, definite proportions, and multiple proportions, plus the early ideas that shaped modern chemistry.

Dalton’s Laws and Early Atomic Ideas | JoVE K12

chemistry

JoVE Core - Química dá vida a conceitos gerais de química usando vídeos de animação fáceis de entender. Além disso, nos vídeos Cientistas em ação, demonstramos experimentos de pesquisa clássicos e originais realizados atualmente por cientistas em laboratórios em todo o mundo.

Physical Science

PS.PSc.1.4

PS.PSc.1.5

Louisiana Student Standards for Science

High School

Matter And Its Interactions

HS-PS1-2

HS-PS1-3

HS-PS1-7

motion-and-stability-forces-and-interactions

Motion And Stability: Forces And Interactions

HS-PS2-6

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Atoms

Structure And Properties Of Matter

Atomic structure

Physical Geology

Minerals

Atoms and elements

Tennessee Academic Standards

Matter and Its Interactions

CHEM1.PS1.2

CHEM1.PS1.11

Virginia  Standards of Learning

HIgh School

CH.2

CH.2.a

PS.2

PS.2.a

Minnesota Academic Standards in Science

2.2.1 9C.1.2.1.2

Arizona Science Standards

HS.P1

HS.P1U1.1

HS+C.P1

HS+C.P1U1.1

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

Texas Essential Knowledge and Skills

CHEM.6

CHEM.6.D

Alabama Course of Study Science

9-12.C.1.1

9-12.C.1.1.a

9-12.C.1.1.b

9-12.PS.3.4.a

Next Generation Science Standards

HS-PS1-1

Earth and Space Science

Earth’s Place in the Universe

HS-ESS1-2

Florida Department of Education

SC.912.E.5

SC.912.E.5.2

SC.912.P.8

SC.912.P.8.3

Chemistry and Physics

IPC.7

IPC.7.A

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

South Carolina College and Career Ready Science Standards

C-PS1-1

C-PS1-2

C-PS1-3.

C-PS1-7

Motion and Stability: Forces and Interactions

C-PS2-6.

Georgia Standards of Excellence

SC1.

Atomic Models: Size, Charge, and Structure

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 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.

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 ...

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.

Dalton’s Laws and Early Atomic Ideas

Description

Transcript

Tags

More videos by Standards