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Properties of Matter
Term | Definition |
---|---|
Physical Change | a change in size, shape, or the state of matter without a change in chemical properties. |
Chemical Change | a change that occurs when one or more substances change into entirely new substances with different properties. |
Law of Conservation of Mass | matter is not created nor destroyed in any chemical or physical change. |
Atom | the smallest particle of an individual element |
Proton | a subatomic particle that has a positive charge and that is found in the nucleus of an atom |
Neutron | a subatomic particle that has no charge and that is found in the nucleus of an atom |
Electron | a negatively charged particle that orbits the nucleus of an atom. |
Atomic Number | the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. |
Atomic Mass Number | the sum of the numbers of protons and neutrons in the nucleus of an atom |
Electron Cloud | a region around the nucleus of an atom where electrons are likely to be found |
Nucleus | an atom's central core, containing protons and neutrons. |
Periodic Table | a chart that organizes elements based upon electron arrangements and their properties |
Chemical Symbol | a 1-3 set of letters used to represent an element, the first letter is always capitalized and all subsequent letters are lowercase |
Metal | an element that is shiny and conducts heat and electricity well |
Nonmetal | elements that are poor conductors of heat and electric current |
Metalloids | elements with properties that fall between those of metals and nonmetals (some are used as semiconductor chips in the computer industry) |
Groups or Families | vertical columns on the periodic table, elements share similar chemical properties, and generally have the same number of valence electrons |
Periods | elements that are in the same horizontal row on the periodic table-these elements share the same number of orbitals also known as energy levels and shells |
Chemical Reaction | the process by which atoms are rearranged chemically to form new substances, chemical bonds can be broken, formed, or both |
Chemical Formula | chemical symbols and numbers that tell the scientist which atoms are present and exactly how many in a substance |
Chemical Equation | the representation of a chemical reaction in words or symbols, this shows the scientist what happens over time during a chemical change, this includes reactants and products |
Reactants | The substances present before a reaction takes place |
Products | The substances formed as a result of a chemical reaction |
Law of Conservation of Energy | the law that states that energy cannot be created or destroyed but can only be changed from one form to another |
Exothermic Reaction | a chemical reaction that releases energy by light or heat |
Endothermic Reaction | a chemical reaction that absorbs energy, usually in the form of heat |
Mixture | A composition of two or more substances that are not chemically combined with each other and are usually capable of being separated |
Solution | a mixture of 2 or more substances that are the same throughout, sugar in water is an example |
Solute | The name for the substance that is dissolved in a solution, in a solution of salt and water, the salt is the solute |
Solvent | the substance that dissolves the solute, generally the largest part of the solution, in a solution of salt and water, the water is the solvent |
Concentration | the amount of substance (solute) dissolved in a given volume of solution (solvent)- for example, the amount of salt dissolved in water |
Acid | a substance that increases the number of hydronium (H3O) ions in a solution, lemon juice in water is an example |
Base | a substance that increases the hydroxide (OH) ions in a solution, soap in water is an example |
Salt | compounds that can be formed during the reaction of an acid and a base, they are always a combination of a metal and a nonmetal |
Neutralization Reaction | the reaction between an acid and a base, the chemical combination is acid + base --> salt + water |