Based on the successive ionization energies of an unknown el…

Based on the successive ionization energies of an unknown element in the table provided, how many valence electrons does the element have?  Successive Ionization energies Number of Electrons Removed Ionization Energies (kJ/mol)  1 1000 2 2000 3 5000 4 7,500 5 21,000 6 23,000 7 25,000