Chemistry revision Atoms elements and compounds Atom-the smallest part of an element that can still be recognized as an element Element-a substance made up of only one type of atom. An element cannot be broken down chemically into any simpler substance Nucleus-middle of the atom‚ which contains protons and neutrons Electron-tiny particle‚ which surrounds the nucleus with a negative charge Compound-when two elements react and combine together which contain more than one element. There
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Notes on the history of the atom In 1897 the British physicist Joseph John (J. J.) Thomson (1856–1940) discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube‚ an area being investigated by numerous scientists at the time. Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of &quotbodies much smaller than atoms&quot that he calculated as having a very large value
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Atoms are the smallest entities which resemble the properties of an element and cannot be broken down into smaller parts. Molecules are formed when two or more atoms are combined. This formation can happen in a variety of ways. When two oxygen atoms join O2 is formed‚ and when three oxygen atoms join O3 or ozone is formed. Both of these have different properties. Different atoms can also combine to form molecules. Hydrogen combines with sulfur to form H2S and hydrogen and oxygen also combine
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nuclei of atoms in particular patterns. You will discover these patterns (and how electrons sometimes act like passengers boarding a bus) with the Electron Configuration Gizmo™. To begin‚ check that Lithium is selected on the PERIODIC TABLE tab. 1. The atomic number is equal to the number of protons in an atom. How many protons are in a lithium atom? ________3_____ 2. A neutral atom has the same number of electrons and protons. How many electrons are in a neutral lithium atom? ______3_______
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The notion of the atom all stared about 450 BC when a Greek scholar starting think when can something break on more‚ when are the pieces at their smallest‚ this mans name was Leucippus. Leucippus also had pupil who also thought the same way as Leucippus‚ his name was Democritus. They developed there ideas and when Democritus died his theory summed up briefly was that everything in the world was made of tiny pieced that could not be broken up any more. That how the word atom was derived from the Greek
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Introduction Atoms‚ molecules‚ compounds and mixtures‚ although they may not seem it‚ are different. Atoms make up all of the above and elements. They are made an equal amount of protons and electrons. Molecules are made when two or more atoms connect chemically. Like molecules‚ compounds are made when two or more atoms connect chemically. Unlike molecules‚ the atoms need to be two or more different elements. Mixtures are made of two or more compounds or elements. Mixtures can look completely the
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n° = 20 e- = 18 2- D) Ca E) S ____________________________________________________________________________ 5) What mass in grams does 2.87 moles of sodium atoms have? 25 A) 1.39 x 10 B) 66.0 C) 8.01 D) 1.39 x 10 24 E) 1.73 x 10 24 ____________________________________________________________________________ 6) How many potassium atoms are contained in 15 g of potassium? 23 26 24 A) 2.3 × 10 B) 3.5 × 10 C) 9.0 × 10 D) 1.6 × 10 24 25 E) 3.3 × 10 ____________________________________________________________________________
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1.dote (dt) intr.v. dot·ed‚ dot·ing‚ dotes To show excessive fondness or love: parents who dote on their only child. DOTE‚ Span. law. The property which the wife gives to the husband on account of marriage. .. It is divided into adventitia and profectitia; the former is the dote which the father or grandfather‚ or other of the ascendants in the direct paternal line‚ give of their own property to the husband; the latter (adventitia) is that property which the wife gives to the husband‚ or that
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nuclear energy was linked to military purpose. The Atoms for Peace speech from Eisenhower in 1953 helped to change this point of view. In his speech he persuaded the world increase the researches within the nuclear power field with the focus on the energy possibilities‚ and start to decrease the potential destructive nuclear weapons. He shifted the focus from nuclear energy from war and fear to an open and peaceful way of generating energy (Atoms for Peace). The Dutch government already saw nuclear
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plants‚ animals and humans became endangered by the rise in temperatures and carbon levels. It was then that Carla‚ a carbon atom was born at the Sahara desert. At night‚ Carla and her friends went outside to watch the stars peacefully. It had never occurred to them that the night would bring a sudden kidnap. All of Carla’s friends and Carla were attached to two oxygen atoms. Unfortunately‚ Carla fainted during the kidnap so when she woke up‚ she took the surprise of no longer being carbon but carbon
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