Question

why is 17th group of periodic table called halogen?

Answer 1

$<b><font color = green>●•••••••☆Hello User☆•••••••●</font> 《《Here is your answer》》 <hr size = 3 width = 300 color = yellow ><font color = orange> ‍‌‌‌ The seventeenth group contains mainly 5 elements which are flourine , chlorine , bromine , iodine , astatine . These are called halogen as these element reacts with first group elements i.e. alkali metal to form their respective salts. The word HALOGEN is a Greek word which means salt forming elements : ( Halo = salt ; Gen = elements ) </font> <hr size = 3 width = 300 color = yellow > <font color = green>●•••••••☆Brainly Star☆•••••••●</font></b> <b>॰॰॰॰॰॰॰॰॥ॐ 卐 ☪ ✝ ॥॰॰॰॰॰॰॰॰</b>$

Answer 2

Because  it have only 7 valence electron in its outermost shell and require only 1 electron to comolete its octave