The Periodic Table Revision Cards for the Chemistry test next week 3.0 / 5 based on 1 rating ? ChemistryThe Periodic TableGCSE Created by: Samuel StrijdomCreated on: 02-12-10 11:18 Atoms and Elements Atoms make up everything Atoms consist of protons, neutrons and electrons Protons are positive Neutrons are neutral Electrons are negative The greek philosopher- Democritus- proposed that the physical world consisted of atoms 1 of 5 Putting elements in order Each element contains just one type of atom Each atom has the same number of protons This is called the atomic number The number of protons and neutrons added together is the mass number or the nucleon number. 2 of 5 Electron Structures Electrons are aranged in shells around the nucleus of the atom Each electron shell can hold a maximum amount of electrons The first shell can hold a maximum of two electrons The second and third shells can hold up to eight electrons 3 of 5 Chemical Shorthand We can use a shorthand to write down the particles in an atom The larger number is the mass number The smaller number is the atomic number 4 of 5 Isotopes In every element each atom has the same number of protons. In most elements, there are different variations with varying numbers of neutrons Atoms of the same number but with different numbers of neutrons are called isotopes Some isotopes are reactive They decay over time and become less radioactive 5 of 5
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