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Chpt. 2 Atoms, Ions, and Molecules

Terms in this set (21)

cathode rays
streams of electrons emitted by the cathode in a partially evacuated tube
electron
a subatomic particle that has a negative charge and essentially zero mass
radioactivity
the spontaneous emission of high energy radiation and particles by materials
beta (B) particles
a radioactive emission that is a high energy electron
alpha (a) particles
a radioactive emission with a charge of 2+ and a mass equivalent to that of a helium nucleus
nucleus (of an atom)
the positively charged center of an atom that contains nearly all the atoms mass
protons
a positively charged subatomic particle present in the nucleus of an atom
neutron
an electrically neutral (uncharged) subatomic particle found in the nucleus of an atom
atomic mass units (amu)
unit used to express the relative masses of atoms and subatomic particles; it is exactly 1/12 the mass of one atom of carbon with six protons and six neutrons in its nucleus
dalton (Da)
a unit of mass identical to 1 atomic mass unit
ion
an atom of group of atoms that has net positive or negative charge
isotopes
atoms of an element containing different numbers of neutrons
nuclide
the nucleus of a specific isotope of an element
atomic number (z)
the number of protons in the nucleus of an atom
nucleon
either a proton or a neutron in a nucleus
mass number (A)
the number of nucleons in an atom
periodic table of the elements
a chart of elements in order of their atomic numbers and in a pattern based on their physical and chemical properties
average atomic mass
a weighted average of masses of all isotopes of an element, calculated by multiplying the natural abundance of each isotope by its mass in atomic mass units and then summing these products
natural abundance
the proportion of a particular isotope usually expressed as a percentage, relative to all the isotopes of that element in a natural sample
polyatomic ions
charges groups of two or more atoms joined together by covalent bonds
oxoanions
polyatomic ions that contain oxygen in combination with one or more other elements
THIS SET IS OFTEN IN FOLDERS WITH...