why is bromine classified as p-block element?

Answer 1

Because its highest energy electron occupies a p-orbital.
Here is the electron configuration:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5

Answer 2

P Block Element

Answer 3

The p-block of the periodic table of the elements consists of the last six groups minus helium (which is located in the s-block). In the elemental form of the p-block elements, the highest energy electron occupies a p-orbital.

I would define p-orbital, but I would need to use scientific characters that I don't know how to type. Go to the Wikipedia article on "p-block" and click on the link to "p-orbital".

Answer 4

Because the highest energy electron occupies a p-orbital as you can see in its electronic configuration:

[Ar] 3d10 4s2 4p5

The last electron applying aufbauprinzip and Pauli exclusion principle, is located in subshell 4p5