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lesson 8
Question | Answer |
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atom | The smallest particle of an element, made of electrons, protons, and neutrons. |
nucleus | The tiny, very dense, positively-charged region in the center of an atom; made up of protons and neutrons. |
electron cloud | The area surrounding the nucleus of an atom where the electrons are found. |
electrical charge | A property of matter; electrons are negatively charged; protons are positively charged; the numbers of protons and electrons in a material determine the charge of the material. |
Proton, p+ | A positively-charged subatomic particle of the nucleus of an atom that contributes to the mass of the atom. |
Neutron, n0 | A subatomic particle of the nucleus of an atom that is without charge that contributes to the mass of an atom. |
electron | A negatively-charged subatomic particle that orbits the atomic nucleus. |
subatomic particles | Particles that are smaller than the atom. |
Element | A pure substance that cannot be separated into simpler substances by physical or chemical means. |
atomic number | The number of protons in the nucleus of a single atom. |
chemical symbol | A one or two letter notation used to represent an atom of a particular element. |
atomic mass | The mass of an atom, approximately equal to the number of protons and neutrons in the atom. |
groups | The columns on a Periodic Table that arrange the elements by the number of electrons that are in the outermost shell. |
periods | The rows in a Periodic Table that classify the elements by the number of electron shells. |
metal | Most elements are metals. They are typically solid, shiny, malleable, and good conductors of heat and electricity. |
non-metal | Elements typically not shiny, usually a gas or brittle solid, not malleable, and poor conductors of heat and electricity. |
metalloids | Elements that have properties of both metals and non-metals; sometimes referred to as semiconductors. |
noble gases | Unreactive non-metals in Group 18 of the Periodic Table. |
electron shell | A specific area where electrons of the same energy level are found. |
valance electrons | The electrons in the outermost energy level of an atom that influence how an element will react with other substances. |
energy level | A state in which matter can exist with a quantifiable amount of energy and distinct from other states with different amounts of energy. |
reactivity | at which a chemical substance tends to undergo a chemical reaction; significantly influenced by valence electrons of the reacting substances. |
outermost electron cloud | The area surrounding the nucleus of an atom where the electrons are found. |
Net Charge | The sum of negative and positive charges. |
ions | Form as a result of the loss or gain of electrons and are identified by the overall net charge. |
chemical reaction | The process by which one or more substances change to produce one or more different substances |
precipitate | A solid that is deposited from a solution |
endothermic | A process that absorbs heat |
exothermic | A process that releases heat |
chemical formula | A shorthand notation that uses chemical symbols and numbers as subscripts to represent the type and number of atoms that are present in the smallest unit of the substance. |
reactants | A substance that takes part in and undergoes change during a reaction |
products | Substances produced during chemical reactions |
coefficient | A number placed in front of a chemical symbol or formula in order to balance the equation |
subscript | A number written below and to the right of an atomic symbol in a chemical formula that shows the number of a specific type of atom present |
chemical formula | A shorthand notation that uses chemical symbols and numbers as subscripts to represent the type and number of atoms that are present in the smallest unit of the substance |
balanced equation | A symbolic representation of a chemical reaction in which both sides of the equation contain equivalent numbers of atoms of each element. The mass and charge must be balanced on both sides of the reaction. |