Structure of matter

All matter consists of elements, for example hydrogen, oxygen, iron. The basic unit of any element is the atom, which cannot be further subdivided by chemical means. The atom itself is an arrangement of three t) es of particles. 

1 Protons. These have unit mass and carry a positive electrical 

2 Neutrons. These also have unit mass but carry no charge. 

3 Electrons. These have a mass about 2000 times less an that of 

Protons and neutrons make up the central part of the nucleus of the atom their internal structure is not relevant here. The electrons take up orbits around the nucleus and, in an electrically neutral atom, the number of electrons equals the number of protons. The element itself is defined by the number of protons in the nucleus. For a given element, however, the number of neutrons can vary to form different isotopes of that element. A particular isotope of an element is referred to as a nuclide. A nuclide is identified by the name of the element and its mass, for example carbon-14. There are 90 naturally occurring elements additional elements, such as plutonium and americium, have been created by man, for example in nuclear reactors. 

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David Turnbull, in his illuminating Commentary on the Emergence and Evolution of Materials Science (Turnbull 1983), defined materials science broadly as the characterisation, understanding, and control of the structure of matter at the ultramolecular level and the relating of this structure to properties (mechanical, magnetic, electrical, etc.). That is, it is Ultramolecular Science . In professional and educational practice, however, he says that materials science focuses on the more complex features of behaviour, and especially those aspects controlled by crystal... 

J. Perrin (Paris) the discontinuous structure of matter, and especially for the discovery of sedimentation equilibrium. 

To learn chemistry, you must become familiar with the building blocks that chemists use to describe the structure of matter. These indude-... 

Regularities observed in the behavior of gases have contributed much to our understanding of the structure of matter. One of the most important regularities is Avogadro s Hypothesis Equal volumes of gases contain equal numbers of particles (at the same pressure and temperature). This relationship is valuable in the determination of molecular formulas—these formulas must be known before we can understand chemical bonding. 

These new facts about electrical phenomena can be incorporated into our particle model of the structure of matter if we again allow some... 

This success of the atomic theory is not surprising to a historian of science. The atomic theory was first deduced from the laws of chemical composition. In the first decade of the nineteenth century, an English scientist named John Dalton wondered why chemical compounds display such simple weight relations. He proposed that perhaps each element consists of discrete particles and perhaps each compound is composed of molecules that can be formed only by a unique combination of these particles. Suddenly many facts of chemistry became understandable in terms of this proposal. The continued success of the atomic theory in correlating a multitude of new observations accounts for its survival. Today, many other types of evidence can be cited to support the atomic postulate, but the laws of chemical composition still provide the cornerstone for our belief in this theory of the structure of matter. 

Thermodynamic, statistical This discipline tries to compute macroscopic properties of materials from more basic structures of matter. These properties are not necessarily static properties as in conventional mechanics. The problems in statistical thermodynamics fall into two categories. First it involves the study of the structure of phenomenological frameworks and the interrelations among observable macroscopic quantities. The secondary category involves the calculations of the actual values of phenomenology parameters such as viscosity or phase transition temperatures from more microscopic parameters. With this technique, understanding general relations requires only a model specified by fairly broad and abstract conditions. Realistically detailed models are not needed to un-... 

Such an approach is consistent with constructivism and follows the principle of induction by going from the macro to the submicro level. Note that the opposite approach, which starts from the structure of matter and follows a productive/receptive approach model, is quite common in chemistry education. 

Numerous studies have shown that students have great difficulties when trying to grasp concepts such as that of the molecule and the atom, i.e., when trying to move from the macro to the submicro level, and vice versa. Various researchers (e.g. Abraham, Williamson, Westbrook, 1994 Brook, Briggs, Driver, 1984, Haidar Abraham, 1991, Lee, Eichinger, Anderson, Berkheime, 1993, Novick Nuss-baum, 1981) have investigated students alternative conceptions. Herron (1978), Johnstone (1991) and Tsaparhs (1997) have stated the position that students have difficulties with concepts and topics relevant to the structure of matter. 

Keig, P. F., Rubba, P. A. (1993). Translations of the representations of the structure of matter and its relationship to reasoning, gender, spatial reasoning, and specific prior knowledge. Journal of Research in Science Teaching, 30(%), 883-903. 

Pfundt, H. (1982). Untersuchungen zu den Vorstellungen, die Schuler vom Aufbau der Stoffe en-twickeln [Investigations of the concepts students develop about the structure of matter]. Der Physikunterricht, 26, 51-65. 

State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Yangqiao Xi Road 155, PO Box 143 350002 Fuzhou, Fujian China... 

Analytical Chemistry is the science of chemical measurement. Its object is the generation, treatment and evaluation of signals from which information is obtained on the composition and structure of matter. 

Much of the electromagnetic spectrum has been used to investigate the structure of matter in the laboratory but the atmospheric windows restrict astronomical observations from Earth. Irritating as this is for astronomers on the ground, the chemical structure of the atmosphere and the radiation that it traps is important to the origins of life on Earth. The light that does get through the atmosphere, however, when analysed with all of the tools of spectroscopy, tells the molecular story of chemistry in distant places around the Universe. 

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