The Atomic Structure of the Atom - Animated Presentation

Subatomic Particles
The basic conception of a subject now known as subatomic particle physics dates back to 500 BC when the Greek philosopher Leucippus and his pupil Democritus suggested that matter consists of small, indivisible particles, which they called atoms. For more than 2000 years after this, the notion of atoms lay in obscurity. For quite a long time, people believed that all matter consisted of four elements: earth, fire, air, and water. We now know that atoms do exist, and that some particles smaller than atoms also exist. These subatomic particles are divided into two main groups, the leptons and the hadrons. The best known lepton ("light" particle) is the electron. In order to account for the emission of electrons from the nucleus, the neutrino, an essentially massless neutral particle was postulated. The muon and the tau, both much more massive than the electron, comprise the rest of the lepton family. The hadrons are divided into two groups, the mesons and the baryons. Protons and neutrons are baryons. Mesons and baryons are made of smaller particles called quarks. There are six different quarks: up, down, charmed, strange, top, and bottom. While these are cool names, they convey nothing about the distinct properties of the quark. Each quark comes in three different colors: red blue and green. Again, the color label has nothing to do with the quark's appearance. Baryons are composed of three quarks, mesons are composed of a quark and an antiquark. Now that you have probably been thoroughly confused, move on, and hopefully that confusion will go awaySubAtomic Particles | Basic Structure of an Atom | Atomic Number, Mass Number, and Isotopes | Avogadro's Number, The Mole, and Atomic Weight | Top of the page The picture below is an example of the arrangement of the particles in an atom. Most of the atom is just empty space. The rest of the atom consists of a positively charged nucleus of protons and neutrons that are surrounded by a cloud of negatively charged electrons. The nucleus is the center of the atom. An atom is an extremely small particle of matter that retains its identity during chemical reactions. During the latter nineteenth century a series of experiments showed that atoms are comprised of smaller particles. An atom consists of a nucleus and one or more electrons surrounding the nucleus. The nucleus, the core of the atom, has the majority of the mass of the atom and a positive charge. An electron is a very light particle which circles the nucleus. It has a negative charge. In an electrically neutral atom, the number of electrons equals the positive charge on the nucleus. The nucleus of the atom is composed of smaller particles called neutrons and protons. A proton has a positive charge equal in magnitude to the negative charge of an electron. This means that in an electrically neutral atom, the postive of charge the protons, combined with the negative charge of the electrons, would result in no charge because they would cancel each other out. A proton's mass, however, is a whopping 1836 times that of the electron. A neutron, however, has a mass almost identical to a proton's, but it has no electrical charge associated with it. Particle Location Weight Charge Proton Nucleus 1.0073 amu PositiveNeutron Nucleus 1.0087 amu Neutral Electrons Electron Cloud 0.000549 amu Negative SubAtomic Particles | Basic Structure of an Atom | Atomic Number, Mass Number, and Isotopes | Avogadro's Number, The Mole, and Atomic Weight | Top of the page The atomic number of an element is what distinguishes it from all other elements. An atom's atomic number is the number of protons there are in the nucleus. Hydrogen's atomic number is 1. Helium's atomic number is 2. Any atom that has an atomic number of 1 is a hydrogen atom no matter how many electrons or neutrons the atom has. The mass number is the number of neutrons added to the number of protons. The mass number of the most common isotope can be obtained from the periodic table. If you take the decimal number on the periodic table and round it to the nearest whole number, you have the mass number. For example the atomic weight of Iron(Fe) is 55.847. When rounded it gives a mass number of 56. The atomic number of Fe is 26. so most Fe atoms have 30 (56-26) neutrons. In addition, all neutral Fe atoms have 26 protons and 26 electrons. Atoms of the same element with a different number of neutrons are called isotopes. The most common isotope of an element is the one that is on the periodic table. he above graphic shows two isotopes of Hydrogen. The picture on the left is the most common isotope of hydrogen with one electron and one proton. The picture on the right is another isotope of hydrogen with one proton, one electron, and a neutron. The most common isotope of uranium is uranium-238 which has 92 protons, 92 electrons, and 146 neutrons. Another isotope is uranium-235 with 92 protons, 92 electrons, and 143 neutrons.

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[NeutronHex]

2:36 the 3rd summary is correct but that doesn't include ions - cations & anions , right?

[NeutronHex]

0:10 ... oh the amount of times ive drawn that in my spare time

[ALittleLamb1997]

You made my study 100% easier since the notes are in irish. Thanks :)