$\text{F}_2 > \text{Cl}_2 > \text{Br}_2 > \text{I}_2$

$\text{I}_2 > \text{Br}_2 > \text{Cl}_2 > \text{F}_2$

$\text{Cl}_2 > \text{Br}_2 > \text{F}_2 > \text{I}_2$

$\text{Br}_2 > \text{I}_2 > \text{F}_2 > \text{Cl}_2$

$\text{HClO}$

$\text{HClO}_2$

$\text{HClO}_3$

$\text{HClO}_4$

$\text{NO}\text{(g)} + \text{O}_3\text{(g)} \longrightarrow \text{NO}_2\text{(g)} + \text{O}_2\text{(g)}$

$2\text{KI}\text{(aq)} + \text{H}_2\text{O}\text{(l)} + \text{O}_3\text{(g)} \longrightarrow 2\text{KOH}\text{(aq)} + \text{I}_2\text{(g)} + \text{O}_2\text{(g)}$

$\text{H}_2\text{O}_2\text{(l)} + \text{O}_3\text{(g)} \longrightarrow \text{H}_2\text{O}\text{(l)} + 2\text{O}_2\text{(g)}$

$\text{PbS}\text{(s)} + 4\text{O}_3\text{(g)} \longrightarrow \text{PbSO}_4\text{(s)} + 4\text{O}_2\text{(g)}$

$+1$

$-1$

$+3$

$-3$