John Dalton's Atomic Theory
All Atoms of a given element were exactly alike. Atoms of different elements could join to form compounds.
J J Thomson's Plum Pudding Model of the Atom
each atom was a sphere filled with a positively charged fluid. The fluid was called the "pudding." Scattered in this fluid were electrons known as the "plums."
Ernest Rutherford's Nuclear Model of the Atom
the atom as having a central positive nucleus surrounded by negative orbiting electrons. This model suggested that most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space.
Quantum Model of the Atom
an atomic model in which electrons are treated as waves; also called the wave mechanical model of the atom
an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties
an atom, radical, or molecule that has gained or lot one or more electrons and has a negative or positive charge
Periodic Table of the Elements
A chart of the chemical elements, arranged in three rows, corresponding to the number of electron shells in their atoms
the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements
Russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements (1834-1907)
an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons
Avg. atomic mass
the weighted average of the masses of all naturally occurring isotopes of an element
an element that conducts heat and electricity poorly and that does not form positive ions in an electrolytic soloution
an element or compound that conducts electric current better than an insulator but not as well as a conductor
one of the elements of Group 1 of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium)
Alkaline Earth metals
one of the elements of Group 2 of the periodic table (beryllium, magnesium, calcium, strontium, barium, and radium)
one of the metals that can use the inner shell before using the outer shell to bond
one of the elements of Group 17 of the periodic table (fluorine, chlorine, bromine, iodine, and astatine); halogens combine with most metals to form salts
an non-reactive element of Group 18 of the periodic table (helium, neon, argon, krypton, xenon, or radon) that has eight electrons in its outer level (except for helium, which has two electrons)
Shiny, reactive metals found in Period 6 from #57-71. Some of these elements are used to make steel and one is found in computer screens to show color.
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 12g of carbon-12