The number of atoms found in each element is equal to Avogadro's number which is equal to 6.022 x 1023 atoms per mole element.
1. 5.40 gram of Boron is equal to 3x 1023 atoms2. 1.5055 x 1023 atoms K3. 2.31 x 1022 atoms K4. 7.72 x1019 atoms Pt5. 3.06 x1011 atoms Au