What are Halogens?

About Halogens:

• Halogens are any of the six non-metallic elements that constitute Group 17 (Group VIIa) of the periodic table.
• The halogen elements are:
  • fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts).
• The word halogen means "salt-producing” because halogens react with metals to produce many important salts, of which sodium chloride—table salt, or halite—is best known.
• Properties:
  • Halogens are so reactive that they do not occur as free elements in nature. They are the most reactive nonmetals.
  • The halogen atoms carry seven valence electrons in their outermost electron shell.
    • This accounts for their higher reactivity and tendency to gain one electron and form ionic bonds or share electrons with other elements to form covalent bonds.
  • Among all the halogens, fluorine is the most reactive, and Iodine is the least reactive of all.
  • In combined form, fluorine is the most abundant of the halogens in Earth’s crust. 
  • Halogens are the only group on the periodic table that has elements in the solid, liquid, and gas phases at room temperature.
  • At normal temperature and pressure, chlorine and fluorine are gasses, bromine is a liquid, and iodine and astatine are solids.
  • They are powerful oxidizing agents.
  • They have very high electronegativities.
  • Halogens have a tendency to form hydrogen halides, which are potent acids when they combine with hydrogen.