The incorrect match among the following is:

We evaluate the correctness of each periodic trend:

1. Ionisation Enthalpy (Period 2): generally increases across a period. However, Nitrogen ($2s^2 2p^3$) has a stable half-filled p-orbital configuration, making it harder to remove an electron compared to Oxygen ($2s^2 2p^4$). Thus, $IE_1(N) > IE_1(O)$. The correct order is $B < C < O < N$. The given option ($B < C < N < O$) is incorrect.
2. Electron Gain Enthalpy (Group 17): Generally becomes less negative down the group. However, Fluorine is anomalous; due to its small size, strong electron-electron repulsion makes adding an electron less favorable than in Chlorine. Thus, Chlorine has the highest negative electron gain enthalpy. The correct magnitude order is $I < Br < F < Cl$. This match is correct.
3. Metallic Radius (Group 1): Radius increases down the group as new shells are added. Order: $Li < Na < K < Rb$. This match is correct.
4. Ionic Size (Isoelectronic Species): For species with the same number of electrons ($10e^-$), radius decreases as nuclear charge (Z) increases. Order: $Al^{3+} (Z=13) < Mg^{2+} (Z=12) < Na^+ (Z=11) < F^- (Z=9)$. This match is correct.