Chemistry
Terms
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- atomic number
- The number of protons in an atom's nucleus
- hypothesis
- a tentative theory about the natural world
- theory
- a well-substantiated explanation of some aspect of the natural world; Theories answer the question of Why things happen.
- ion
- a particle that is electrically charged (positive or negative)
- molecular compound
- a compound made up of two non metals; sharing electrons, smallest unit is a molecule
- hydrogen
- a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas, very low melting point and density
- annealing
- make less brittle by heat and gradual cooling
- core electrons
- The electrons in the inner shells of an atom; these electrons are not involved in forming bonds.
- atomic mass unit
- A unit equal to one twelfth the mass of a carbon-12 atom.
- halogens
- the elements of Group 17 (fluorine, chlorine, bromine, iodine, and astatine), contains nonmetals; 7 electrons in its outermost energy level; very reactive; poor conductors of electric current; never in its uncombined form in nature; combine with most metals to form salts
- deposition
- exothermic, gas to solid
- valence electrons
- The electrons in the outermost shell (main energy level) of an atom; these are the electrons involved in forming bonds.
- transition metals
- Groups 3-12, 1-2 electrons in the outer energy level, less reactive than alkali-earth metals, shiny, good conductor of thermal energy and electrical current, high density
- cation
- a positively charged ion; metals form cations, named the same as the metal
- protons
- positively charged particles located in the nucleus
- tempering
- hardening something by heat treatment, makes metal springy
- homogenous
- uniform mixture
- calorie
- unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure
- binary molecular compounds
- two nonmetals
- physical properties
- Are characteristics that can be measured or detected by the senses.Color, size, odor, and density are phyisical properties.
- heterogenous
- composed of unlike parts, different, diverse; not uniform mixture
- binary ionic compound
- metal and nonmetal, either type I or type II
- law
- a generalization that describes recurring facts or events in nature; laws answer the question of What will happen. Quantifies with numbers
- precision
- closeness of a set of measurements of the same quantity made in the same way
- neutrons
- no charge; mass of 1 amu; the number of these may vary in atoms of the same element (isotopes); the symbol is n
- potential energy
- stored energy the amount of potential energy of an object depends on its position or condition (nuclear, chemical)
- chemical properties
- properties that relate how a substance transforms or reacts with another substance
- subliming
- solid to a gas (does not go through liquid stage first)
- accuracy
- (mathematics) the number of significant figures given in a number
- binary compound
- chemical compound composed of only two elements
- rare earth metals
- very rare; U-92 was the last naturally occurring element.
- alkali metals
- Group 1, 1 electron in outer level, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium
- molecular element
- 7 mulit-atom molecules that never exist alone. (diatomic) Mr. BrINCHlHOF
- hardening
- makes brittle by heating and then cooling quickly, less flexible
- alkali earth metals
- an elemnet in group 2, harder, higher melting point, and denser than alkali metals. Reactive, but less than corresponding alkali metal
- periodicity
- The habit or characteristic of recurrence at regular intervals.
- pure substance
- a sample of matter, either a single element or a single compound, that has definite chemical and physical properties
- periodically
- having periods, or repeated cycles
- isotopes
- same element, but diff atomic mass number b/c diff # of neutrons
- ionization energy
- The amount of energy needed to completely remove an electron from an atom
- Polyatomic ionic
- metal and poliatomic ion, either type I or type II
- binary acids
- H and a nonmetal
- periodic law
- the law that states that the repeating chemical physical properties of elements change periodically with the atomic numbers of the elements.
- oxyacids
- H and a polyatomic ion
- noble gases
- one of the elements of group 18 of the periodic table(helium, neon,argon, krypton, xenon, and radon); noble gases are unreactive, Contains nonmetals that are unreactive. Full outermost energy level except helium which has 2.
- elements
- a pure substance that is made up of only one kind of atom
- chemistry
- the science of matter
- anion
- a negatively charged ion; non metals form anions, named by changing the ending of the name to -ide
- mixture
- (chemistry) a substance consisting of two or more substances mixed together (not in fixed proportions and not with chemical bonding)
- ionic compound
- Consists of a positive ion (metal) and a negative ion (non metal) with an overall charge of zero, no individual molecule units, a 3-D array of cation and anions made of formula units. (ex. NaCL (1:1) (repetition of ratio))
- mass numbers
- the sum of neutrons and protons in the nucleus of an atom.
- electrons
- Found in electron shells around nucleus. Have negligible mass and negative charge.
- kinetic energy
- energy of motion (electrical, heat or thermal, light or radiant)