The successive ionization enthalpy of element are given as 240,1000,1800,4500,7000 identify the element.

Here the IE values slowly increases and the 5th IE value is high among others. So it indicates the removal of 5th electron from ns²np⁶ configuration or from some duplet configuration. Thus the element is belonging to carbon family. May be its carbon. 
C⁶ - 1s²2s^​22p². After the removal of 4 electrons the configuration becomes 1s² configuration which is a stable configuration.