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Atoms and PT
Reimer Atoms and Periodic Table Study Guide - 8th
Question | Answer |
---|---|
matter | anything that has mass and takes up space |
atom | small particle that makes up most types of matter and is made up of smaller particles called protons, neutrons and electrons |
law of conservation of matter | states that matter is neither created nor destroyed, only changed in form |
electron | negatively charged particle only changed in form |
nucleus | central part of the atom |
proton | positively charged, heavy particle contained in the nucleus of all atoms |
neutron | neutral particle that is present in the nucleus of all atoms (has the same mass as the proton) |
element | a substance that can not be broken down into smaller substances |
electron cloud | region surrounding the nucleus of an atom |
atomic number | number of protons in the nucleus of an atom; whole number that tells how many protons are in the nucleus of each atom of an element |
atomic mass | number of neutrons plus the number of protons in the nucleus of an atom |
isotope | atoms of the same element that have different numbers of neutrons in the nuclei |
radioactive decay | release of nuclear particles and energy from unstable atomic nuclei |
half-life | time needed for one-half the mass of a sample of a radioactive isotope to decay; can vary from fractions of a second to billions of years |
periodic table | a chart in chemistry that lists the elements in order on increasing atomic number |
period | a horizontal row on the periodic table |
group (or family) | a vertical column on the periodic table |
metal | element that is a good conductor of electricity and heat, is usually a solid at room temperature and usually is shiny, ductile, and malleable |
non-metal | element that is a poor conductor of heat and electricity and may be a gas or a brittle solid at room temperature |
metalloid | element that shares some properties with metals and nonmetals |