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CH. 17-18
| Term | Definition |
|---|---|
| element | any pure substance that is made of only one kind of atom. |
| alchemy | aspects of chemistry, philosphy, religion, metallurgy, medicine and art. |
| periodicity | the repitition of certain properties at regular intervals when elements were placed in the order of atomic mass |
| metals | belong to families with relitivley few valience electrons. |
| nonmetals | hold electrons tightly, properties are very different from metals. |
| periods | ---- horizontal rows of elements ---- |
| electronn affinity | deals with the strength of the attracton of electrrons |
| chemical symbols | berzelium's notation consisting of one or two letters derived from the elements name |
| monatomic | occur as single atoms |
| diatomic | hydrogen nitrogen oxygen fluorine chlorine bromine iodine |
| octet rule | full 8 electrons in their valence electricity level |
| electron affinity | how well it holds and attracts electrons |
| electronegativity | an atoms ability to attract and hold atoms when bonded to other atoms |
| ionic bond | between metals and nonmetals |
| covalent bond | mostly between nonmetals |
| metallic bond | atoms bond by sharing their easily lost electrons among atoms |
| Lewis structure | molecular notation |
| double bonds | stronger than single bonds |
| triple bonds | each atom must share three electrons to complete its octet |
| polyatomic molecules | molecules made up of three or more atoms |
| polar covalent bond | uneven electron sharing |
| nonpolar bonds | bonds with no polarity. formed by diatomic elements |
| covalent compounds | consist of covalently bonded molecules |
| ionic compounds | formed by ionic bonds |
| crystal lattice | mobile ions clump together with opposite charges |
| formula unit | the smallest ratio of elements in an ionic compound |
| unit cells | groupings of ions |
| electron sea theory | a model of the bonding of metals and their properties |