Does beryllium (Be) or Sodium (Na) have the same electron arrangement as Magnesium (Mg)? Why?

Na has the most similar configuration. Na electron configuration: 1s²2s²2p⁶3s¹ or [Ne] 3s₁. Mg electron configuration: 1s²2s²2p⁶3s² or [Ne] 3s². Be electron configuration: 1s²2s² or [He] 2s². Na and Mg are right next to each other in the same period

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3