The formation of compound takes place by the combination of two or more different atoms. The combination of atoms takes place in a definite proportions. Compounds with different proportions of atoms have different properties.
Water ([tex]H_2O[/tex]) is composed of the same element as hydrogen peroxide ([tex]H_2O_2[/tex]) that is hydrogen ([tex]H[/tex]) and oxygen ([tex]O[/tex]). The combination of hydrogen and oxygen atoms in water is in [tex]1:2[/tex] ratio whereas the combination of hydrogen and oxygen atoms in hydrogen peroxide is in [tex]2:2[/tex] ratio. So, the properties of water and hydrogen peroxide are different as the arrangement of atoms is different in the compound.
Hence, the correct option is they have different properties because the arrangement of atoms is different.
