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The Atom
Term | Definition |
---|---|
Atom | The basic particle from which all elements are made;the smallest particle of an element that has the properties of that element.(pg.73) |
Electron | A tiny, negatively charged particle that moves around the outside of the nucleus of an atom.(pg.74) |
Energy Level | A region of an atom in which electrons of the same energy are likely to be found.(pg.76) |
Atomic number | The number of protons in the nucleus of an atom.(pg.78) |
Isotope | An atom with the same number of protons and a different number of neutrons from other atoms of the same element.(pg.79) |
Neutron | A small particle in the nucleus of the atom, with no electrical charge.(pg.77) |
Nucleus | In cells, a large oval organelle that contains the cell's genetic material in the form of DNA and controls many of the cell's activities; The central core of an atom which contains protons and neutrons.(pg.75) |
Mass number | The sum of protons and neutrons in the nucleus of an atom.(pg.79) |
Proton | Small, positively charged particles that are found in the nucleus of an atom.(pg.75) |
Atomic mass | The average mass of all the isotopes of an element.(pg.81) |
Chemical symbol | A one-or two-letter representation of an element.(pg.83) |
Group | Elements in the same vertical column of the periodic table; also called family.(pg.87) |
Period | A horizontal row of elements in the periodic table.(pg.86) |
Periodic table | An arrangement of the elements showing the repeating pattern of their properties.(pg.82) |