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Chemistry: The Basics
Chemistry: The Basics

... – Discovered by James Chadwick in 1932. – Actual mass = 1.67 x 10-24 grams – No charge ...
Elementary my dear Watson review
Elementary my dear Watson review

... are involved and the numbers tell us how many atoms of each kind are involved. For example, water (H20) is made up of 2 atoms of hydrogen and 1 atom of oxygen. For example, carbon dioxide (CO2) is made up of 1 atom of carbon and two atoms of oxygen. ...
Test 1 Guide
Test 1 Guide

... 1) Neutrons have almost no mass (in amu) and no charge. 2) The fact that 2 different elements may have atoms with the same atomic mass violates Dalton’s atomic theory. 3) Deuterium differs from hydrogen in the number of protons it has. 4) In the quantum mechanical model of the atom, electrons are co ...
Matter Vocab Part 4
Matter Vocab Part 4

Chemistry Honors Unit 2 Study Guide Atomic Theory Mr. Brown Use
Chemistry Honors Unit 2 Study Guide Atomic Theory Mr. Brown Use

... Law of Definite Proportions/Composition = Chemical compounds always contain the same elements in exactly the same proportions by mass regardless of the amount or source of the sample. EX. NaCl always contain 39.34% by mass of Na and 60.66% by mass of Cl. Law of Multiple Proportions = If two or more ...
Modern Physics
Modern Physics

... from the nucleus for the hydrogen atom is 2 ao. Find the probability of finding the 1-s electron at a distance greater than 2 ao according to quantum mechanics. ...
1. Modern Physics
1. Modern Physics

Topic 7: Atomic and nuclear physics 7.1 The atom
Topic 7: Atomic and nuclear physics 7.1 The atom

... is somehow excited, then the electrons will leave the ground state and move to a higher energy state. As soon as this happens they transition back to lower energy states radiating energy in the process. The set of wavelengths of light emitted by the atoms of the element is called its emission spectr ...
Introduction_to_Geochemistry_Pre-Lecture_Quiz
Introduction_to_Geochemistry_Pre-Lecture_Quiz

Review Notes - Biochemistry
Review Notes - Biochemistry

Problem Set 05
Problem Set 05

... a nitrogen molecule (N2) from its ground state (n=0) to the n=1 rotational state (for N2, d=0.11 nm). [You can check your result by noting that rotational spectra for small molecules are generally in the microwave region: 0.1mm→10cm]. ...
3. Represents an atom that has four valence electrons.
3. Represents an atom that has four valence electrons.

... 9. Which of the responses contains all the statements that are consistent with the Bohr theory of the atom (and no others)? (I) Only orbits of specific radii, corresponding to certain definite energies, are permitted for electrons in an atom. (II) An electron in a permitted orbit has a specific ener ...
File
File

... atom: The smallest particles that make up matter. proton: a subatomic particle that has a positive charge and that is located in the nucleus of an atom. (The number of protons in the nucleus is the atomic number, which determines the identity of an element.) neutron: a subatomic particle that has no ...
First Semester Honors Chemistry Exam Review (2011
First Semester Honors Chemistry Exam Review (2011

chapter 7 – cyu
chapter 7 – cyu

Models of the Atom:
Models of the Atom:

... Atoms of the same element are identical. Atoms of different elements are not the same. Atoms of different elements can physically mix together or can chemically combine with one another in simple wholenumber ratios to form COMPOUNDS. ...
ATOMS
ATOMS

Nuclear - Orangefield ISD
Nuclear - Orangefield ISD

... ◦ Aristotle rejected Atomic Theory  Respected for ideas on nature, physics, astronomy, etc., so most ignored Democritus’ ideas ...
Ch 2 Atomic History
Ch 2 Atomic History

... given a negative charge. Gravity forces the drops downward. The applied electric field forces the drops upward. When a drop is perfectly balanced, the weight of the drop is equal to the electrostatic force of attraction between the drop and the positive ...
power point notes
power point notes

... WAY! He thought that only 4 elements actually exist: water, air, fire and earth ...
Simple Harmonic Oscillator
Simple Harmonic Oscillator

... Never express yourself more clearly than you are able to think. Prediction is very difficult, especially about the future. - Niels Bohr ...
The Nature of Matter
The Nature of Matter

atoms, molecules, and matter (2)
atoms, molecules, and matter (2)

Chapter 4: Struct of Atom
Chapter 4: Struct of Atom

The Quantum Mechanical Model of the Atom
The Quantum Mechanical Model of the Atom

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Atomic theory



In chemistry and physics, atomic theory is a scientific theory of the nature of matter, which states that matter is composed of discrete units called atoms. It began as a philosophical concept in ancient Greece and entered the scientific mainstream in the early 19th century when discoveries in the field of chemistry showed that matter did indeed behave as if it were made up of atoms.The word atom comes from the Ancient Greek adjective atomos, meaning ""uncuttable"". 19th century chemists began using the term in connection with the growing number of irreducible chemical elements. While seemingly apropos, around the turn of the 20th century, through various experiments with electromagnetism and radioactivity, physicists discovered that the so-called ""uncuttable atom"" was actually a conglomerate of various subatomic particles (chiefly, electrons, protons and neutrons) which can exist separately from each other. In fact, in certain extreme environments, such as neutron stars, extreme temperature and pressure prevents atoms from existing at all. Since atoms were found to be divisible, physicists later invented the term ""elementary particles"" to describe the ""uncuttable"", though not indestructible, parts of an atom. The field of science which studies subatomic particles is particle physics, and it is in this field that physicists hope to discover the true fundamental nature of matter.
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