Final Exam How does Matter Change.doc - How does matter changes As we study chemistry the first vocabulary that we learn is matter what is matter then

Final Exam How does Matter Change.doc - How does matter...

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How does matter changes? As we study chemistry, the first vocabulary that we learn is matter; what is matter then? One general meaning of matter is something that occupies space and has mass. Everything in the Earth and probably the universe are make of matter. Matter includes things you can see (such as trees, soil, and paper) and things that you can’t see (such as air). Matter can changes in three ways: physical changes, chemical changes, and nuclear changes (which we will discuss in the next few paragraphs), every time a changes occurs, new things or energy are released. It is very important for us to study matter because since the matter makes up everything in our living environment, so if we want to improve our ways of living, then we need to study and understand the way different matter behaves in order to make changes. Secondly, by manipulating the properties of matter, we are able to create new kind of substances that’s good for us (ex: medicines), nuclear bombs are also created through nuclear changes, but that’s a different story. Although matter makes up everything in our environment, it is not the smallest unit in the chemistry world though. Matter is also makes up of something call “atom”, the word comes from Greek word atomos , which means “not to be cut” or “indivisible”. There is a long history of how the atoms are developed; in as early as Greek, Greek philosopher Democritus already proposes the theory of atoms. Then there are Dalton’s Model, Thomson’s Model, Rutherford’s Model, The Bohr Model, and the Wave Quantum Model. There are the model or theory of the atoms proposed throughout history, some are right, some are proven wrong today, but no matter what, they have make some significant development in atom history. Anyway now we know that atom is composes of a nucleus and electrons; a nucleus is located in the center of an atom, inside the nucleus is the
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protons and neutrons. Protons have a positive charge, since like charge repels like charge (the nature of electric charge), neutrons are needed to balance between protons, neutron has no charge. The number of protons and neutrons in a nucleus make up the atomic mass of an element. Besides the nucleus, there are energy levels scattered around the nucleus, the electrons, with negative charges, are located on these energy levels. Between the nucleus and energy level are mostly empty spaces. There are many different kinds of atoms that exist in the world, each has different number of protons, neutrons, and electrons, which they arrange themselves as element. As you look at the periodic table, each elements are arranged according to their atomic number (protons) and atomic mass (protons plus neutrons), however the atomic mass is not always constant, each same element sometimes can have different atomic mass due to the amount of neutrons that they have, it is known as isotope. When different elements join together, they form compound. There are tow kinds of bonding which elements join together: ionic bonding and covalent bonding. Ionic bonding happens when a element gives its electrons to
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