It is a Compound.
Water can't be a mixture because it is chemically bonded and cannot be separated into H2 and O by physical means.
And water cannot be an element, because it is made of atoms of different types [H and Oxygen]
Answer:
ns²np⁵
Explanation:
The electronic configuration of elements of halogen group ends with 7 electrons in its outer most shell and they distributed as ns²np⁵.
Such as Cl (17 electron): 2,8,7 which is 1s²2s²2p⁶3s²3p⁵.