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6 Sci Chapter 6
6 Science Chapter 6
| Term | Definition |
|---|---|
| chemistry | the study of what substance are made of, and how one substance can be changed into another |
| matter | anything that takes up space & has mass |
| weight | a measure of the pull of gravity upon an object. can change from place to place |
| mass | the amount of matter that makes up an object |
| density | the amount of matter (mass) in one unit of volume (space) |
| atoms | the tiny particles that make up matter |
| nucleus | the tiny, extremely dense core of an atom |
| electrons | tiny particles in an atom that circle the nucleus at tremendous speed |
| electron cloud | the shield or cloud formed by fast-moving electrons in an atom that prevents other atoms from moving into the same space |
| neutrons | one of the two kinds of particles that make up the nucleus of an atom; has a neutral charge |
| protons | one of the two kinds of particles that make up the nucleus of an atom; has a positive charge |
| neutral | lacking as electrical charge |
| shell | a set of electrons in an atom that orbits the nucleus at roughly the same distance |
| atomic number | the number of protons in an atom |
| element | a substance that is composed of only one type of atom bonded together |
| compound | a substance that is composed of more that one type of atom bonded together |
| periodic table of elements | a chart constructed by Dmitri Mendedeev to arrange the elements in such a way as to group similar elements together |
| nickel | a very hard metal that is used to make stainless, rechargable batteries, tanks to hold corrosive chemicals, and certain coins |
| chromium | "chrome"; a shiny metal often applied to polished steel to prevent it from rusting |
| lead | the denest of everyday metals; used to make car and track batteries, wheel weights, and firearms ammunition |
| zinc | a metal often used to coat steel to prevent it from rusting; also used in flashlight batteries |
| sulfur | an oderless, yellow solid called brimstone in the Bible; flammable and burns easily |
| carbon | basic building block of ALL LIVING things; found in two forms, graphite and diamond |
| silicon | a semimetal that is an ingrediant in sand, quartz, and glass; in pure form, used to make computer chips |
| phosphorus | a waxlike solid with two forms, white and red |
| hydrogen | the simplest atom with one proton and one electron which is also a colorless and odorless gas used in chemical factories and as a rocket fuel. |
| potassium | a common alkali metal found in the rocks, soils, and oceans of the earth; does not occur naturally in pure form |
| magnesium | a strong but lightweight alkali metal used in parts for airplanes and some cars |
| calcium | the most common alkaline earth metal; an ingredient in calcium carbonate |
| sodium | a common alkali metal that is as ingredient in table salt and lye; also used in street lights |
| metals | the elements located to the left and center in the periodic table; most have a lustrous silvery color and are at room temperature |
| nonmetals | the elements located at the right side of the periodic table; include many solids and several gases |
| halogens | the elements in the next to last column of the periodic table; highly reactive, showing a tendency to form compounds with alkali and alkaline metals |
| sublime | to turn directly from a solid to a gas (such as iodine does when heated) |
| noble gases | the elements in the last column of the periodic table; are gases and do not combine with other elements except under very unusual circumstances |
| molecule | a tiny group of two or more atoms that are bonded tightly together |
| molecular compound | a compound that is composed of individual molecules |
| crystal | a geometric arrangment of atoms |
| ionic compounds | a compound composed of charged atoms or groups of atoms |
| chemical reaction | a process in which atoms of elements or compounds are rearranged to form new substances |
| combustion | burning; a chemical reaction in which a substance reacts rapidly with oxygen |
| plutonium | the most abundant of the transuranium minerals |
| osmium | the densest element |
| mercury | the only metal that is liquid at room temperature |
| bromine | a nonmetal (halogen) that is liquid at ordinary room temperatures and pressures |
| oxygen and nitrogen | the main ingredients of air; together make up almost 99% of the earth's atmospere |
| iodine | a halogen that sublimes instead of melts when heated; it is also added to salt. |
| diamond | the hardest of all known substances |
| oxygen | most abundant element at the surface of the earth |
| semimetals, nonmetals and metals | three main groups of elements |