Why Are the Halogens So Reactive

The Group 7A(17) elements form many ionic and covalent compounds metal and nonmetal halides, halogen oxides, and oxoacids. Like the alkali metals, the halogens have an electron configuration one electron away from that of a noble gas whereas a 1A metal atom must lose one electron, a 7A nonmetal atom must gain one. It fills its outer level in either of two ways  

Gaining an electron from a metal atom, thus forming a negative ion as the metal forms a positive one 

Sharing an electron pair with a nonmetal atom, thus forming a covalent bond 

The haiogens show a generai decrease in bond energy as bond iength increases. However, F2 deviates from this trend because its smaii, ciose, eiectron-rich atoms repei each other, thereby iowering its bond energy. 

Atomic mass Valence e configuration Common oxidation states 

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