in what temperature does phosporous and sodium start burning

Dear student,

Different elements have  different ignition temperatures or we can say burning temperature.

Phosphorus have ignition temperatures of approximately 86°F.

​​​​​​Ignition of sodium  depends on exposure of surface area for example,  vapour ignites at room temperature  and droplets ignite at 250°F  .
sodium burns with the equation, 
4Na + O₂ → 2Na₂O

Regards!!!