| A | B |
|---|
| periodic table | elements are arranged by increasing atomic number and by changes in physical and chemical properties |
| group | the vertical columns in a periodic table numbered 1 through 18 |
| electron dot diagram | uses the symbol of the element and dots to represent the electrons in the outer energy level |
| period | the horizontal rows of elements on the periodic table |
| metal | element that is typically a hard, shiny solid, malleable, and a good conductor of heat and energy |
| malleable | ability of metals and alloys to be rolled or hammered into thin sheets |
| ductile | ability of metals to be drawn into wires |
| metallic bonding | occurs because electrons move freely among a metal's positively charged ions and explains properties such as ductility and the ability to conduct electricity |
| radioactive element | element, such as radium, whose nucleus breaks down and emits particles and energy |
| transition element | elements in Groups 3 and 12 of the periodic table |
| nonmetal | element that usually is a gas or brittle solid at a room temperature, is not malleable or ductile, is a poor conductor of heat and electricity, and typically is not shiny |
| diatomic molecule | a molecule that consists of two atoms of the same element |
| salt | compound formed when negative ions from an acid combine with positive ions from a base |
| sublimation | the process of a solid changing directly to a vapor without forming a liquid |
| metalloid | element that shares some properties with metals and some with nonmetals |
| allotrope | different forms of the same element having different molecular structures |
| semiconductor | materials having conductivity properties between that of metals and nonmetals and having controllable conductivity parameters |
| transuranium element | elements having more than 92 protons, all of which are synthetic and unstable |
