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Chemistry
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 | A positively-charged subatomic particle of the nucleus of an atom that contributes to the mass of the atom |
Neutron | 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 |
Valence 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 | Rate 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 so;id 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 |