Term
|
Definition
| all matter is composed of atoms. |
|
|
Term
|
Definition
| composed of negatively charged particles called electrons |
|
|
Term
|
Definition
| negatively charged particle that surrounds a positively charged nucleus |
|
|
Term
|
Definition
| central core of the atom. it consist of protons and neutrons |
|
|
Term
|
Definition
| positively charged. Elements identified by number of protons it has |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the nu,ber of protons in the nucleus (also the # of electrons) |
|
|
Term
|
Definition
| the # of protons plus neutrons in the nucleus |
|
|
Term
|
Definition
mass number - atomic number
(cant have fraction: round then subtract ex. 18.998= 19) |
|
|
Term
|
Definition
a a= mass number
X x= atomic symbol
z z= atomic number |
|
|
Term
|
Definition
| atoms of the same element that have different numbers of neutrons |
|
|
Term
|
Definition
| all atoms of the same element have the atomic number and the same number of protons. However, atoms do not necessarily have the same number of neutrons |
|
|
Term
|
Definition
1/12th the mass of a carbon-12 atom (masses of all other atoms calculated relative to this)
1 amu= 1.66 x 10^-24g |
|
|
Term
|
Definition
| the force that holds the nucleus together |
|
|
Term
| radionuclides (radioactive isotope) |
|
Definition
| nucleus whose nuclei undergo spontaneous decay |
|
|
Term
| radioactive decay (radioactivity) |
|
Definition
| the spontaneous process of nuclei undergoing a change by emmitting particles or rays. Can occus in 3 ways= aplha, beta, and gamma decay |
|
|
Term
| radioactive decay equation |
|
Definition
A-> B + b
a= parent nucleus
B= daughter nucleus
b= emitted particle or ray |
|
|
Term
|
Definition
(massive) the disintergration of a nucleus with th emission of an alpha particle, equivalent to a helim nucleus
4
He
2 |
|
|
Term
|
Definition
the disintegration of a nucleus by the emission of a beta particle, which is an electron. A neutron is tansformed into a proton and electron. The proton remains in the nucleus, and the electron is emitted
0 (relative mass)
e (particle)
-1 (relative charge)
1 0
n-> p + e
1 -1 |
|
|
Term
|
Definition
|
|
Term
|
Definition
when a nucleus emits a gamma ray and becomes a less energetic form of the same nucleus (usually from an excited state * as a product of alpha or beta decay)
204 204
Pb *--> Pb + gamma
82 82 |
|
|
Term
|
Definition
| the rate if decay of a given radionuclide, which is the time it takes for half of the nuclei in a sample to decay |
|
|
Term
|
Definition
| atom of molecule that has gained or loat -e to form a negative or positive charge` |
|
|
Term
|
Definition
| the splitting of a large nucleus by bombarding it with neutrons to produce smaller nuclei, neutrons, and large amounts of energy |
|
|
Term
|
Definition
| fixed compositions and identical properties; cannot be separated by physical |
|
|
Term
|
Definition
| a substance in which all the atoms have the same number of protons (ex. F, Na, Cr) |
|
|
Term
|
Definition
| a substance composed of two or more elements chemically bonded in a fixed ration (ex. NaCl, HF,H20) |
|
|
Term
|
Definition
| composed of varying proportions of 2 or more substances that are just physically mixed, not chemically bonded; can be separated by physical means |
|
|
Term
|
Definition
| nonuniform composition -- at least two components can be observed (ex. Italian Dressing) |
|
|
Term
|
Definition
| looks uniform throughout -- appears as one substance (ex. wine, coffee) |
|
|
Term
|
Definition
| two or more forms of the same element that have different bonding structure in the same physical state |
|
|
Term
|
Definition
| diamond, graphite, fullerenes |
|
|
Term
|
Definition
| moleculer oxygen (O2) and ozone (O3) |
|
|
Term
|
Definition
| an electrically neutral particle composed of two or more atoms chemically bonded; can be atoms of the same or different elements (ex. CO2, H2O, H2) |
|
|
Term
|
Definition
| (H2, N2, O2, F2, Cl-2 gas) Br2-liquid, I2- solid |
|
|
Term
|
Definition
mendeleev (1869) first detailed and useful, demonstrated how elements with similar physical and chemical properties recur at regular intervals (or periodically)
Periods: horizontal rows
groups: vertical columns |
|
|
Term
| two main groups of elements |
|
Definition
|
|
Term
|
Definition
| (left) tend to lose electrons in chemical reactions to form positive ions; good conductors; left side of periodic table |
|
|
Term
|
Definition
| alkah metals--highly reactive, can easily lose 1 electron to form +1 ions |
|
|
Term
|
Definition
| alkaline earth metals--reactive form +2 ions |
|
|
Term
|
Definition
| transition metals, less reactive can form multiple ions |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| (right)elements whose atoms tend to gain (or share) electrons to form negative ions; poor conductors, right side of periodic table. |
|
|
Term
|
Definition
| halogens, highly reactive, easily gain 1 electrons to form -1 ions; typically react with group 1 elements to form salts. |
|
|
Term
|
Definition
| noble gases, nonreactive; no change; fall electron orbitals. |
|
|
Term
|
Definition
| electrons are found in various energy levels in atoms |
|
|
Term
|
Definition
| bonding by the attraction between oppositely charge ions; a transfer of electrons occurs between a metal and a nonmetal. |
|
|
Term
|
Definition
| bonding by the sharing of one or more pairs of electrons; convalent bonding occurs betwwen 2 nonmetals. |
|
|
Term
|
Definition
| the name of the first atoms (metal) stays the same. the second or nonmetals name, changes to end in -ide. |
|
|
Term
| naming covalent compounds |
|
Definition
| must be two nonmetals, numeral prefixes are used to denote how many atoms of each element are in the compound, the name of the first element does not change, and if there is only one atom of the first element, no prefix is used, second elements name changes to end in -ide. |
|
|
Term
|
Definition
| metals lose e- to form positive ions |
|
|
Term
|
Definition
| nonmetals gain e- to form negative ions |
|
|
Term
|
Definition
| for ionic compunds to form the total electric charge must be zero. |
|
|
Term
|
Definition
| the outer shells of an atom |
|
|
Term
|
Definition
| electrons in the outer shells of an atom |
|
|
Term
|
Definition
|
|
Term
|
Definition
| number of energy levels or shells that contain electrons |
|
|
Term
|
Definition
| for groups 1 and 2: the number of valence electrons |
|
|
Term
|
Definition
| the number of valence electrons= group number- 10 |
|
|
Term
|
Definition
| have both ionic and covanlent character; groups of covalently bonded atoms that have either lost or gained electrons |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| naming covalent compounds |
|
Definition
name of the first element does not change and if there is only one atom of the first element, no prefix is used
the second elements name always has a prefix and changes to end in -ide |
|
|
Term
|
Definition
| metals lose e- to form positive ions |
|
|
Term
|
Definition
| nonmetals gain e- to form negative ions |
|
|
Term
|
Definition
| the total electric charge must be zero to form |
|
|
Term
|
Definition
| enriched uranium has more... |
|
|
Term
|
Definition
the process by which smaller nuclei combine to form larger ones, also with the release of large amounts of energy.
(source of energy from the sun and stars) |
|
|
Term
|
Definition
| the control rods of a nuclear reactor are made of special material called... |
|
|
Term
|
Definition
| aprox 117 and 26 are synthetic (manmade) |
|
|
Term
|
Definition
| the release of neutrons them bombard nuclei and further fission occurs |
|
|
Term
|
Definition
| a minimum quantity of radioactivity material... is needed to keep the reaction going |
|
|
Term
|
Definition
| atomic bombs and nuclear reactors |
|
|
Term
|
Definition
| contains 99.3% 238U and only .7% is fissionable 235U isotope |
|
|
Term
|
Definition
| must be concentrated or "enriched" in order to create either a self-sustaning or expanding train reaction |
|
|
Term
|
Definition
| 235U has been enriched to about 3%, enough for self sustaining chain reaction |
|
|
Term
|
Definition
| require an enrichment of 90% or more 235U, enough for a sudden release of energy |
|
|
