Transcript Slide 1
Basic Chemistry Why are we studying chemistry if this class is EARTH SCIENCE? • Geology – – – – – rocks… made from minerals… made from molecules… which are made up of … … atoms • Meteorology – – air… made from molecules… which are made up of… atoms • Oceanography – water … –made up of molecules… which are made up of… atoms • Astronomy – space… made up of nothing… –what matter IS in space is made from molecules… which are made up of … atoms The Periodic Table • http://periodic.lanl.gov/default.htm Periodic Table A tabular arrangement of the elements according to their atomic numbers so that elements with similar properties are in the same column. Most important reference tool in chemistry • Group: Elements in a column (group) have the same number of electrons in their outer orbital . • Period: Elements in a row (period) have the same number of atomic orbitals The Periodic Table Vocabulary • element – a substance that cannot be broken down into simpler substances by ordinary chemical or physical means • atom – the smallest particle of an element, with all the properties of this element that can combine with other atoms to form a molecule Sub-atomic particles • proton – positively charged particle in the atom’s nucleus • neutron – neutral atomic particle in an atom’s nucleus (has mass slightly higher than a proton) ** (At. Mass – At. Number = # of neutrons)** • electron – negatively charged particle that spins around the nucleus of an atom. The electron cloud has a radius 10,000 times greater than the nucleus • Atomic Number – number of protons in an atom’s nucleus (also equal to the number of electrons in the atom’s electron cloud) • Atomic Mass – the mass of the nucleus, and electron cloud of that atom • Mass Number – mass of an element gives the average number of protons and neutrons in an atom • Atomic Symbol – one or two letters chosen to represent an element ** (At. Mass – At. Number = # of neutrons)** • Atomic Number • Atomic Symbol • Atomic Mass • ion – an atom or groups of atoms having an electric charge as a result of losing or gaining one or more electrons • isotope – atoms of the same element having different numbers of neutrons, with resultant different atomic masses – change a proton different element – change an electron an ion – change a neutron an isotope • molecule – two or more chemically bonded elements ; the smallest part of a compound with all the properties of that compound.(O2 , H2O) • compound – a pure substance made of two or more different elements that cannot be separated by physical means (water, salt); usually having properties unlike those of its elements .(H2O) • mixture – any combination of compounds & elements (atmosphere, rocks, ocean water) • solution – a mixture of different substances occurring without a chemical reaction; usually one substance is dissolved in another & the solution is homogeneous (salt water) Chemical bonds force of attraction that holds atoms or ions together • ionic bond – exchange of electrons to form opposite charged ions (NaCl) ionic bond – exchange of electrons to form opposite charged ions (NaCl) The Periodic Table • http://periodic.lanl.gov/default.htm covalent bond – 2 atoms share electrons creating a molecule metallic bond – many atoms share many electrons (among a lattice of metal atoms) therefore it makes electricity possible. They are similar to covalent bonds. Properties • physical properties – color, shape, texture, hardness, density, ductility, buoyancy, solubility, etc. • chemical properties – the way something reacts to another substance States of matter • phase change – when a substance in a solid liquid, or gas phase changes from one phase to another, without altering its chemical composition States of matter • solid – an object in which the atoms or molecules are in a fixed position • liquid – atoms or molecules remain close to one another but are free to change positions with • each other • gas – atoms with very little attractive forces that take the shape of the entire container no matter the size or shape • plasma – an electrically neutral, highly ionized gas composed of ions, electrons, and neutral particles • .(H2O)