Science Periodic Table Stuff
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82 terms
Terms | Definitions |
|---|---|
 atom | The smallest particle that can still be considered an element |
| Democritus | Greek philosopher who proposed that matter is formed from small, uncuttable pieces |
| Dalton's model | Which model proposes that an atom is a smooth hard ball that can not be broken down? |
| atoms cannot be divided | Can atoms be divided according to Dalton? |
| atoms of different elements do not have the same atomic mass | Do atoms of different elements have the same atomic mass? |
| An atom of one element cannot be changed into another element with a chemical reaction | Can an atom of one element be changed into another element with a chemical reaction? |
| When atoms of more than one element combine in a set ratio | When are compounds formed? |
| Thomson's Model | What model suggests that an atom has electrons scattered throughout a positively-charged ball? |
| electron | a negatively charged particle |
| Rutherford | Who performed the experiment with the thin sheet of gold foil and the laser? |
| nucleus | a small region in the center of the atom containing protons and neutrons |
| they must have been repelled by the gold atom nuclei | In the gold foil experiment, the foil repelled some of the lasers, which means that _______ |
| Like charges repel each other | Do like charges repel each other? |
| proton | positively charged particles in an atom's nucleus |
| Bohr's Model | What model proposed that electrons are found in specific orbits around the nucleus and that each electron orbit has a different energy level? |
| Cloud Model | What model says that electrons move in a cloud-like region around the nucleus? |
| energy level | The specific amount of energy an electron has |
| neutron | a particle with a neutral charge found in the nucleus |
| amu | measurement unit of atomic mass |
| atomic number | number of protons in an atom is the _______of that atom's element |
| 1,840 | there are _______ electrons in one proton or neutron |
| isotopes | atoms with the same number of protons and different numbers of neutrons |
| mass number | the sum of the protons and neutrons of an isotope |
| atomic mass | average mass of all the isotopes of an element |
| Mendeleev | Russian chemist responsible for the first periodic table |
| atomic mass | There is a pattern of properties in the periodic table when the elements are arranged by _____ |
| periodic table | arrangement of elements showing the repeating pattern of their properties |
| increasing atomic number | modern periodic tables are written in order of ______ |
| chemical symbol | contains one or two letters |
| periods | rows on the periodic table |
| groups | columns on the periodic table |
| left | Metals are shown on what side of the table? |
| right | nonmetals are located on what side of the periodic table? |
| between metals and nonmetals | metalloids are found where on the periodic table? |
| 7 | How many periods are there? |
| 18 | How many groups are there? |
| repeat | The pattern of the properties repeats or does not repeat in each period? |
| metals | elements that are good conductors of electric current and heat |
| luster | a material has a high ______ if it is shiny and reflective |
| malleable | a material that can be hammered or rolled into flat sheets is ______ |
| ductile | A _____ material can be pulled out or drawn into long wires |
| thermal conductivity | the ability of an object to transfer heat |
| electrical conductivity | the ability of an object to carry electric current |
| reactivity | the ease and speed with which an element combines with other substances |
| corrosion | deterioration of a metal because of a chemical reaction in the environment |
| alkali metals | metals of group one, the most reactive metals |
| alkaline earth metals | metals of group 2 |
| transition metals | metals in groups 3-12, less reactive than the alkali and alkalines |
| metals in mixed groups | metals in groups 13-16 |
| lanthanides and actinides | two rows of elements below the main table |
| transuranium elements | Elements that follow uranium, they are made when nuclear particles crash into each other |
| 111 | elements greater than number ______ do not have permanent names or symbols |
| nonmetal | an element that lacks most of the properties of a metal |
| they gain or share electrons | what do nonmetals usually do when they react with other atoms? |
| carbon family | nonmetal family of group 14 |
| nitrogen family | nonmetal family of group 15 |
| diatomic molecule | a molecule made up of two atoms |
| oxygen family | nonmetal family of group 16 |
| halogen family | nonmetal family of group 17 |
| halogen | "salt-forming" |
| fluorine | What is the most reactive element? |
| noble gases | elements in group 18 that hardly react with anything |
| hydrogen | element with the simplest atoms, cannot be grouped with any other family |
| metalloids | elements that have some nonmetal and some metal properties |
| semiconductors | substances that can conduct heat under some conditions but not others |
| radioactive isotopes | unstable isotopes are called ______ |
| radioactive decay | radioactive atomic nuclei release energy and fast-moving particles |
| nuclear reaction | involves the particles in the nucleus of an atom |
| nuclear fission and nuclear fusion | two types of nuclear reactions |
| radioactivty | ability to spontaneously emit radiation |
| alpha particle | consists of two protons and two neutrons and is positively charged |
| beta particle | fast-moving negatively charged electron given off by a nucleus in radioactive decay |
| gamma ray | consists of high energy waves and has no charge |
| a sheet of paper | Alpha particles cannot penetrate ______ |
| a 5 mm thick aluminum sheet | beta particles cannot penetrate _______ |
| a concrete wall one meter thick | gamma rays cannot penetrate _____ |
| half-life | length of time needed for half of the atoms in an isotope sample to decay |
| radioactive dating | process by which scientists calculate how many half-lives have passed since something died |
| radioactive dating, uses in science and industry, uses in medicine, nuclear energy | four uses of radioactive isotopes |
| tracers | radioactive isotopes that can be followed through a chemical reaction |
| high-energy gamma rays | cancer tumors can sometimes be treated how? |
| nuclear fission and nuclear fusion reactions | nuclear energy can be created from radioactivity how? |
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