Name: from atomos to the modern atom
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 17 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Earth and Space Science

Space Systems

3.3.9-12.C

Atomic Structure

Każdy pierwiastek składa się z maleńkich cząstek zwanych atomami. Cząstki te nadają każdemu pierwiastkowi odrębne właściwości fizyczne i chemiczne, takie jak temperatura wrzenia, temperatura topnienia i gęstość.
Wszystkie atomy pierwiastka mają identyczne właściwości, ale różnią się od atomów innych pierwiastków.
Różnice te wynikają z cząstek subatomowych – protonów, neutronów i elektronów.
Zarówno protony, jak i neutrony mają swój udział w masie atomowej, po jednej jednostce masy atomowej każdy, podczas gdy elektrony mają prawie znikomą masę.
Protony i neutrony są skupione w centralnym jądrze. Liczba protonów, równa liczbie atomowej, określa konkretny pierwiastek.
Protony są naładowane dodatnio, a neutrony są nienaładowane, więc jądro ma ładunek dodatni netto.
Chmura ujemnie naładowanych elektronów jest przyciągana do jądra. Chmura ta jest w większości pusta i stanowi większość objętości atomu.
Neutralny atom zawiera równą liczbę protonów i elektronów, znosząc ładunki dodatnie i ujemne i prowadząc do braku ładunku netto.

struktura atomowa

Filozof grecki Demokryt zaproponował, że wszystko na Ziemi składa się z malutkich cząstek zwanych atomami, wywodzących się od greckiego słowa "atomos", co oznacza "niepodzielny". To słowo stanowi pierwowzór współczesnego terminu "atom". W XIX wieku John Dalton sformułował teorię atomową, która w dużej mierze jest nadal aktualna. Przedstawił pięć założeń, aby wyjaśnić, w jaki sposób atomy kształtują świat wokół nas. (1) Cała materia składa się z nieskończenie małych cząstek, czyli atomów. (2) Wszystkie atomy danego pierwiastka są identyczne między sobą, a (3) różnią się od atomów wszystkich innych pierwiastków. (4) Dwa lub więcej pierwiastków mogą się połączyć w stałym stosunku, tworząc związek chemiczny. (5) Atomy nie mogą być ani tworzone, ani niszczone w reakcjach chemicznych, lecz mogą przegrupowywać się, tworząc nowe substancje.

Dalton był tylko częściowo precyzyjny, jeśli chodzi o cząstki, które tworzą materię. Mimo że atomy nie mogą być dalej rozdzielane przez zwykłe procesy chemiczne lub fizyczne, składają się z trzech mniejszych subatomowych cząstek. Pierwsze wskazówki na temat subatomowej struktury pojawiły się, gdy J.J. Thomson odkrył elektron. Naukowcy wiedzieli, że całkowity ładunek atomu jest neutralny, ale model "plum pudding" atoma Thomsona dostarczył nowych informacji dotyczących istnienia cząstki o ładunku ujemnym, sugerując, że elektrony znajdują się rozrzucone wokół obszaru naładowanego dodatnio. Później, Ernest Rutherford przeprowadził eksperyment, pokazując, że większość masy atomu koncentruje się w jądrze, gdzie protony odpowiadają za dodatni ładunek atomu, a małe, naładowane ujemnie elektrony stanowią większość przestrzeni na zewnątrz jądra. To obaliło teorię "plum pudding" Thomsona. W 1932 roku James Chadwick odkrył, że neutron odpowiada za masę obecną w atomie.

Według obecnie przyjętej teorii, protony znajdują się w jądrze atomu, posiadają ładunek dodatni i masę jednostki masy atomowej (AMU). Liczba protonów odpowiada numerowi atomowemu w układzie okresowym i określa tożsamość pierwiastka. Neutrony również znajdują się w jądrze. Nie mają ładunku, ale mają taką samą masę jak protony, co przyczynia się do masy atomu. Elektrony krążą wokół jądra w chmurach. Mają ładunek ujemny i znikomą masę, przyczyniając się do całkowitego ładunku atomu, ale nie do jego masy.

Struktura atomowa

Grecki filozof Demokryt zaproponował, że wszystko na Ziemi składa się z maleńkich cząstek zwanych atomos, co po grecku oznacza "niepodzielny", od których ...

Education

JoVE Core

Anatomy and Physiology

Anatomia i fizjologia

Unit 1

Jednostka 1

Fundamentals of Chemistry

Podstawy chemii

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

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 &quot;indivisible.&quot; 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 not. He also said that elements combine in fixed ratios to form compounds, and that atoms are not created or destroyed in a chemical reaction. Instead, they rearrange to make new substances.

Dalton’s model was only partly complete. Atoms cannot be broken down by ordinary chemical or physical processes, but they do contain smaller subatomic particles. The first major clue came from J. J. Thomson, who discovered the electron. At the time, scientists knew atoms were neutral overall, so Thomson’s plum pudding model suggested that negative electrons were spread through a positively charged material.

Later, Ernest Rutherford carried out an experiment that changed the atomic model. His results showed that most of an atom’s mass is packed into a central nucleus. In this model, protons provide the atom’s positive charge, and the tiny negative electrons take up most of the space outside the nucleus. This finding disproved Thomson’s plum pudding model.

In 1932, James Chadwick discovered the neutron, which explained the mass still present in the atom. In the accepted model today, protons and neutrons are in the nucleus. Protons have a positive charge and a mass of one atomic mass unit, or AMU, each. The number of protons equals the atomic number on the periodic table and defines the element. Neutrons have no charge, but they have about the same mass as protons, so they add to atomic mass. Electrons move in clouds around the nucleus. They have a negative charge and very little mass, so they affect the atom’s overall charge more than its mass.

From Atomos to the Modern Atom

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atomic structure

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

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isotopes and radioisotopes

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electron behavior

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From Atomos to the Modern Atom | JoVE K12

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Louisiana Student Standards for Science

High School

Chemistry

Matter And Its Interactions

HS-PS1-1

Next Generation Science Standards

Earth’s Place in the Universe

HS-ESS1-3

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

South Carolina College and Career Ready Science Standards

Matter and Its Interactions

C-PS1-1

C-PS1-2

C-PS1-3.

motion-and-stability-forces-and-interactions

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C-PS2-6.

Georgia Standards of Excellence

Physical Science

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Atomic Structure of atoms

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3.3.9-12.A

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

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3.3.9-12.D

From Atomos to the Modern Atom

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