Mass of gold nugget = 4.259 g
Calculating the moles of gold from mass and molar mass:
[tex] 4.259 g Au * \frac{1 mol Au}{196.97 g Au} = 0.0216 mol Au [/tex]
Calculating the atoms of Au:
[tex] 0.0216 mol Au * \frac{6.022 * 10^{23} atoms Au}{1 mol Au} = 1.3*10^{22} atoms Au [/tex]
Therefore, [tex] 1.3 * 10^{22} atoms Au [/tex] are present in a gold nugget with a mass of 4.259 g.