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Unit 4 Vocab
Term | Definition |
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Electron | a subatomic particle that has a negative charge |
Nucleus | an atom's central region, which is made up of protons and neutrons |
Proton | a subatomic particle that has a positive charge and that is located in the nucleus of an atom |
Neutron | a subatomic particle that has no charge and that is located in the nucleus of an atom |
Atomic number | the number of protons in the nucleus of an atom |
Mass number | the sum of the numbers of protons and neutrons in the nucleus of an atom |
Isotope | an atom that has the same amount/number of protons (or the same atomic number) as other atoms of the same elements do but that has a different number of neutrons (and thus a different atomic mass) |
Mole | the SI base unit used to measure the amount of a substance whose number of particles is the same as the number of atoms of carbon in exactly 12g of carbon-12 |
Orbital | a region in an atom where there is a high probability of finding electrons |
Valence electron | is found in the outermost shell of an atom and that determines the atom's chemical properties |
Photon | a unit or quantum of light; a particle of electromagnetic radiation that has zero rest mass and carries a quantum of energy |
Periodic law | states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements |
Period (chem.) | a horizontal row of elements in the periodic table |
Period (phys.) | the time it takes a complete cycle or wave oscillation to occur |
Group | a vertical column of elements in the periodic table; elements in this share chemical properties |
Ion | an atom, radical, or molecule that gas gained or lost one or more electrons and has a negative or positive charge |
Metal | an element that is shiny and that conducts heat and electricity well |
Nonmetal | an element that conducts heat and electricity poorly and that does not form positive ions in an electrolytic solution |
Semiconductor | an element or compound that conducts electric current better than an insulator does but not as well as a conductor does |
Alkali metal | one of the elements of Group 1 of the periodic table (Li, Na, K, Rb, Cs, Fr) |
Alkaline-Earth metal | one of the elements of Group 2 of the periodic table (Be, Mg, Ca, Sr, Ba, Ra) |
Transition metal | one of the metals that can use the inner shell before using the outer shell to bond (Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn) |
Noble gas | one of the elements of Group 18 of the periodic table (He, Ne, Ar, Kr, Xe, Rn, Og) and are unreactive |
Halogen | one of the elements of Group 17 of the periodic table (F, Cl, Br, I, At, Ts) and they combine with most metals to form salts |