We evaluate the trends for Group 17 elements (Halogens):

1. Oxidising Power: Fluorine is the strongest oxidising agent due to its high hydration enthalpy and low bond dissociation enthalpy. The trend $F_2 > Cl_2 > Br_2 > I_2$ is correct (Supported by standard electrode potentials: $F_2$ = +2.87 V, $I_2$ = +0.54 V) .
2. Electron Gain Enthalpy: Chlorine has the most negative electron gain enthalpy. Fluorine is less negative than Chlorine due to inter-electronic repulsion in its small 2p subshell. The trend $Cl_2 > F_2 > Br_2 > I_2$ is correct.
3. Electronegativity: Fluorine is the most electronegative element. The trend decreases down the group ($F > Cl > Br > I$). This is correct.
4. Bond Dissociation Energy: One might expect bond energy to decrease down the group as size increases ($F-F > Cl-Cl > ...$). However, due to the very small size of Fluorine, there is strong lone pair-lone pair repulsion between the non-bonding electrons, which weakens the F-F bond. Consequently, the bond dissociation energy of $F_2$ is lower than that of $Cl_2$ and $Br_2$. The correct order is $Cl_2 > Br_2 > F_2 > I_2$. Therefore, the given trend $F_2 > Cl_2 > Br_2 > I_2$ is incorrect.