click below
click below
Normal Size Small Size show me how
Introduction to Chem
Introduction to Chemistry
Term | Definition |
---|---|
Atom | the smallest unit of an element that maintains the properties of that element |
Atomic Number | the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element |
Average Atomic Mass | the weighted average of the masses of all naturally occurring isotopes of an element |
Chemical Bond | an interaction that holds atoms or ions together |
Chemical Equation | a representation of a chemical reaction that uses symbols to show the relationship between the reactants and products |
Chemical Formula | a combination of chemical symbols and numbers to represent a substance |
Chemical Reaction | the process in which atoms are rearranged and chemical bonds are broken and formed to produce a chemical change of an substance |
Chemical Symbol | a one-, two- or three letter abbreviation of the name of an element |
Electron Cloud | a region around the nucleus of an atom where electrons are likely to be found |
Electron | a subatomic particle that has a negative charge |
Endothermic Reaction | a chemical reaction that requires energy input, usually as heat |
Exothermic Reaction | a chemical reaction in which energy is released to the surroundings, usually as heat |
Group | a vertical column of elements in the periodic table; elements in a group share chemical properties |
Law of Conservation of Energy | the law that states that energy cannot be created or destroyed but can be changed from one form to another |
Law of Conservation of Mass | the law that states the mass cannot be created or destroyed in ordinary chemical and physical changes |
Mass Number | the sum of the numbers of protons and neutrons in the nucleus of an atom |
Metal | an element that is shiny and that conducts heat and electricity well |
Metalloid | an element that has properties of both metals and nonmetals |
Neutron | a subatomic particle that has no charge and that is located in the nucleus of an atom |
Nonmetal | an element that conducts heat and electricity poorly |
Nucleus | in physical science, an atom's central region, which is made up of protons and neutrons |
Period | in chemistry, a horizontal row of elements in the periodic table |
Periodic Table | an arrangement of the elements in order of their atomic numbers such that elements with similar properties fall in the same column, or group |
Product | a substance that forms in a chemical reaction |
Proton | a subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of protons in the nucleus is the atomic number, which identifies the identity of an element |
Reactant | a substance that participates in a chemical reaction |
Valence Electron | an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties |