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Atom Vocabulary
8th Grade Science Texas
Term | Definition |
---|---|
atom | The smallest particle of an element that cannot be broken down without losing its properties; basic unit that makes up all matter. |
atomic mass | The average mass of an atom. (protons + neutrons) |
atomic number | The number of protons found in the nucleus of an atom. Oxygen = 8; Carbon = 6. |
electron | A subatomic particle, with a negative charge, found outside the nucleus of an atom. |
element | The simplest form of a molecule made of only one type of atom with a certain number of protons and properties unique to that element. |
Energy level | Refers to the electron configuration outside the nucleus of an atom. |
group number | Numbered columns of the periodic table. Numbers correlate with the number of valence electrons for a neutral atom. |
metal | Elements located to the left of the zigzag line on the periodic table. Generally, these are good conductors, reactive and have shiny luster. Al, Zn, Ag, Au, Cu, Fe |
metalloid | Elements found along the zig-zag of the periodic table that share properties of both metals and non-metals. Boron, Silicon, Germanium, Arsenic, Antimony, etc… |
molecule | Two or more atoms of same or different kinds chemically bonded together. NaCl or Cl2 |
noble gas | Elements found in group 18 of the periodic table. These elements generally do not form compounds with other elements because their outer energy level is full. Helium, Neon, Argon, Krypton, Xenon, etc… |
non-metal | Elements located to the right of the zigzag line on the periodic table. These are generally poor conductors. Cl, Ne, O |
Nucleus | The dense center of an atom containing the protons and neutrons. |
neutron | A subatomic particle with no charge (neutral) found in the nucleus of an atom. |
periods | The numbered rows of the periodic table. Numbers indicate the number energy levels (shells) for an atom. |
Proton | A positively charged subatomic particle that determines an element’s identity. |
subatomic particle | Particles smaller than an atom that combine to form an atom. protons, neutrons, electron |