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Science Vocab 18
Vocabulary note cards for atoms/atomic structure
Terms | Definitions |
---|---|
Atomic Mass | The average mass of all known isotopes of an element. |
Atomic mass Units | defined as the mass of 1/12 of a carbon-12 atom (6 protons, neutrons in the nucleus plus 6 electrons outside the nucleus.) |
Atomic Number | The number of protons a atom contains. |
Atomic Theory | A theory that states that all matter is composed of tiny particles called atoms. |
Chemical Symbol | an abbreviation that represents the name of and element; used in chemicals. |
Electron | A subatomic particle in a atom that is negatively charged and that occupies the energy levels in an atom; electrons are involved in chemical bonds and reactions. |
Energy Levels | a region around the nucleus of an atom where electrons are most likely to be found; only a certain number of electrons can be found in each energy level of an atom. |
Group Of Elements | elements that exhibit similar chemical properties; arranged in columns on the periodic table. |
Isotopes | forms of the same element that have different numbers of neutrons and different mass numbers. |
Mass Number | the total number of protons and neutrons in the nucleus of an atom. |
Neutron | an uncharged particle found in the nucleus of an atom. |
Nucleus | the center core of an atom that contains protons and neutrons. |
Periodic Table Of Elements | a table that visually organizes the similarities between all known elements. |
Proton | a subatomic particle identical with the nucleus of the hydrogen atom; found with neutrons in all atomic nuclei; carries a positive charge. |
Strong Nuclear Force | the force that holds protons together when they are very close together (only 10 to the negative 15th meters apart). |
Subatomic Particles | particles that are smaller than an atom; protons, neutrons, and electrons are subatomic particles. |
Valence Electrons | the electrons in an atom that are involved in the formation of chemical bonds. |