The density of mercury is 13.6 grams per cubic centimeter. complete the steps for converting 13.6 g/cm3 to kg/m3. (1 kg = 1,000 g, 1 m3 = 106 cm3)

1 m³ = 10^6 cm^3. Be careful with transcription!

Converting: 
13.6g/cm³ x (1,000,000 cm³/ 1 m³) = 13,600,000 g/ m³

13,600,000 g/m³ * (1 kg / 1,000g) = 13,600 kg / m³

Answer is 13,600 kg/m³, or 1.36 x 10^4 kg/m³

Determine the  wavelength of light emitted when an electron  in an li2+ ion  makes a transition from an orbital with n  =  6 to an orbital with n  = 5.

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.