Atoms of a given element which have the same number of protons but different numbers of neutrons are called isotopes. Thus‚ isotopes have the same position in the periodic table‚ the same chemical properties and the same atomic charge. The simplest example of an atom with different isotopes is hydrogen. The three isotopes of hydrogen are shown here: The increasing number of neutrons in the nucleus of the hydrogen atom adds mass to the atom and thus each isotope of a given element has a different
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Discuss the impact of Alchemy on the modern science of Chemistry. At the first time human being have found gold - a rare and the most valuable element in the world‚ people are attracted by its shiny and glowing appearance. They are trying to find different ways turning those ordinary base metals into worthy gold. This kind of transformation process started at the Middle Ages‚ named as Alchemy‚ was the initiation of the modern science of Chemistry. Alchemy is a difficult and complicated subject
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I started with answering the question of what sulfur is. Sulfur is known for being a natural element‚ and being used as a chemical. It is commonly seen as a yellow substance that comes in a crystalized form. It is found in volcanic areas‚ and also deep underneath the ground. My research tells me it makes up “0.05% of the Earth’s crust” (Net). When burned‚ its distinctive odor when burned makes it hard to swallow‚ and can make one suffocate. It has the property of burning very easily‚ and has corrosive
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_________________. These synapses are always (excitatory or inhibitory). Advantages of the electrical synapses: 1. _______ signal conduction 2. _____________ activity for a group of neurons. 6. The chemical synapse: Chemical
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AND ATOMIC MASS LAB Prelab A new atomic theory‚ in which all atoms of the same element are identical to one another and equal in mass‚ was proposed by the scientist Dalton. Although the theory had its flaws and was simple‚ it was revolutionary. Scientists became able to study the actual structure and mass of atoms after the discovery of radioactivity. Soon‚ isotopes were discovered‚ as atoms of the same element which have been built up to have different masses. Purpose The purpose of this
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person to discover atoms. His followers would often think that there were multiple kinds of atoms and not just plain atoms. 2.2 – How Do We Classify Matter? Elements – A substance that consists of identical atoms. Today there are 116 known elements. Example – C= Carbon; H= Hydrogen Compounds – A pure substance made up of two or more elements in a fixed ratio by mass. Example – Water is made up of hydrogen and oxygen‚ H20. Mixtures – A combination of two or more pure substances. Example – Blood
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Shelby Brown 8/28/10 Physical and chemical changes lab essay Changes in matter occur every day. There are two types of ways matter can be altered; physically and chemically. Physical changes do not change the composition of the matter while chemical changes occur when one or more substances turn into a completely new substance. Physical changes can be seen through an altering of the substances physical property. A substances physical property is observed and measured without changing
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idea that all things are elements or combinations of elements can be found in the writings of the ancient Greeks and other early peoples. Although this idea may seem simple‚ it is very difficult to decide if a substance is indeed an element or a compound. There were twelve chemical elements discovered in ancient times‚ but it was not known that they were elements. Another 76 elements were discovered between 1557 and 1925. Many mistakes were made in the discovery of the elements and the term ‘chemist’
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Name: Tom Flannigan Title: Physical and Chemical Properties Purpose: To investigate the chemical properties of pure chemical substances. To investigate the physical properties of pure chemical substances. Procedure: For this lab we used four test tubes and poured equal amounts of a substance in each test tube. We then observed the color and odor. We then heated the substance and recorded the observation. The next tube we added cold water and observed the effects‚ then we heated it
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Promethium‚ Pm‚ is the 61st element on the Periodic Table. It was discovered in 1945 by Jacob A. Marinsky. It’s a metal‚ and named after the Greek God Prometheus. It is not naturally occurring‚ but can survive outside of a lab. Promethium has an atomic number of 61‚ which is the number of protons. Its atomic mass‚ protons+neutrons‚ is 145u. It is an isotope. This means that it has a different number of neutrons (84) than the number of electrons and protons (61). Every element changes states of matter
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