Why is group 17 more reactive than group 16?

Answer 1

The elements of this group do not have a stable number of electrons.

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Group 17, the halogens, are extremely reactive (the only non-reactive elements are in group 18, the noble gases, but group 17 elements are more reactive than other group elements) because of their high "effective nuclear charge." An atom wants to have eight electrons in its outer shell, whether it's because it naturally has that many like the group 18 elements do or because it bonded to other atoms and share electrons with them. The closer to eight an atom has on its own, the higher this charge is - which makes it more reactive. Group 17 atoms all have seven electrons in their outer shells, so they are on the hunt for anything they can possibly grab.

For more entertainment, the fewer shells an atom has between its "helium layer" (that lil' shell right around the nucleus with two electrons in it) and the outer shell, the higher this effective nuclear charge is. Because fluorine only has two shells, its effective nuclear charge is as high as it can get...which is why fluorine will react with anything including glass.

Answer 2

Group 1 elements have one valence electron. If they lose one electron, they will attain noble gas configuration and obey octet rule. Hence group 1 elements are reactive and tend to lose one electron.

Group 17 elements have seven valence electron. If they gain one electron, they will attain noble gas configuration and obey octet rule. Hence group 17 elements are reactive and tend to gain one electron.

Answer 3

Because they have to lose and gain only one electron which is easier.

Answer 4

The X-X bonds are weak wheras the bonds formed with other elements are stronger.