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Perodic table
atomic structure and Periodic Table
Term | Definition |
---|---|
Atomic Mass | The average mass of all the isotopes of an element. |
Atomic Number | The number of protons in the nucleus of an atom. |
Proton | small positively charged particles that are found in the nucleus of an atom. |
Neutron | A small particle in the nucleus of the atom, with no electrical charge. |
Electron | A tiny, negatively charged particle that moves around the outside of the nucleus of an atom. |
mass | The amount of matter in an object. |
Periodic Table of Elements | An arranagement of the elements showing the repeated pattern of thier propterties. |
classification | the action or process of classifying something according to shared qualities or characteristics. |
Dimitri Medeleev | Russian chemist who devised the periodic table of the elements. |
Reactivity | The ease and speed with which an element combines, or reacts, with other elements and compounds. |
stable Atom | An atom whose particles that makeup the nucleus are balanced |
unstable atom | An atom whose forces are unbalanced; if the nucleus has an excess of internal energy, may result from an excess of either neutrons or protons. |
charged atom | a charged atom or molecule because the number of electrons do not equal the number of protons in the atom or molecule. I |
ion | An atom or group of atoms that has become electrically charged. |
atomic particles | Any of the various self-contained units of matter (parts of an atom) or energy that are the fundamental constituents of all matter. |
symbol | a letter or pair of letters used to represent a chemical element. |
endothermic reaction | any chemical reaction that absorbs heat from its environment. The absorbed energy provides the activation energy for the reaction to occur. A hallmark of this type of reaction is that it feels cold. |
exothermic reaction | a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy. |
Bohr Model | A diagram that shows electrons orbiting the nucleus of an atom somewhat like planets orbit around the sun.The electrons are pictured as traveling in circles at different shells, depending on which element you have. |
valence electrons | electrons located at the outermost shell of an atom. |
Lewis Dot Model | a representation of the valence electrons of an atom that uses dots around the symbol of the element. The number of dots equals the number of valence electrons in the atom. |
atom | The basic particle from which all elements are made; the smallest particle of an element that has the properties of that element. |
molecule | A neutral group of two or more atoms held together by covalent bonds. |