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Chapter 3
Lessons 1 to 4
| Question | Answer |
|---|---|
| atom | the basic particle from which all elements are made; the smallest particle of an element that has the properties of that element |
| electron | A tiny, negatively charged particle that moves around the outside of the nucleus of an atom |
| nucleus | the central core of an atom which contains protons and neutrons |
| proton | small, positively charged particles that are found in the nucleus of an atom |
| energy level | A region of an atom in which electrons of the same energy level are likely to be found |
| neutron | A small particle in the nucleus of an atom, with no electrical charge |
| atomic number | The number of protons in the nucleus of an atom |
| isotope | An atom with the same number of protons and a different number of neutrons from other atoms of the same element |
| mass number | the sum of protons and neutrons in the nucleus of an atom |
| atomic mass | The average mass of all the isotopes in an element |
| periodic table | An arrangement of elements showing the repeating pattern of their properties |
| chemical symbol | A one or two letter representation of an element |
| period | A horizontal row of elements in the periodic table |
| group | elements in the same vertical column of the periodic table; also called a family |
| metal | A class of elements characterized as by physical properties that include shininess, malleability, ductility, and conductivity |
| luster | The way a material reflects light from its surface |
| malleable | A term used to describe material that can be hammered or roll into flat sheets |
| ductile | A term used to describe a material that can be pulled out to a long wire |
| thermal conductivity | the ability of an object to transfer heat |
| electrical conductivity | The ability of an object to carry an electric current |
| reactivity | the ease and speed with which an element combines, or reacts, with other elements and compounds |
| corrosion | the gradual wearing away of a metal element due to a chemical reaction |
| alkali metal | An element in Group 1 of the periotic table |
| alkaline earth metal | An element in Group 2 of the periotic table |
| transitional metal | One of the elements in group 3-12 of the periotic table |
| non-metal | An element that lacks most of the properties of a metal |
| diatomic molecule | A molecule consisting of two atoms |
| halogen | An element found in group 17 of the periotic table |
| noble gas | An element in group 18 of the periotic table |
| metalloid | An element that has some characteristics of both metals and non metals |
| semiconductor | a substance that can conduct an electric current under some conditions |