How many moles are there in 4.01 x 1024 atoms of zinc?

Answer is 6.66 mol.

Explanation:

According to the Avogadro's constant, 1 mole of substance has 6.022 × 10²³ particles.

Number of Zinc atoms =  4.01 x 10²⁴
Avogadro's constant = 6.022 × 10²³ mol⁻¹
Hence,
      moles of Zinc = number of Zinc atoms / Avogadro's constant
                              = 4.01 x 10²⁴ / 6.022 × 10²³ mol⁻¹
                              = 6.66 mol

It’s the energy source of stars

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.