5.824x10^22 atoms of cobalt are in 5.699 grams of cobalt.
First, determine the number of moles of cobalt you have by dividing the mass of cobalt by the atomic weight of cobalt. So
Atomic weight cobalt = 58.933195
Mole cobalt = 5.699 g / 58.933195 g/mol = 0.096702716 mol
Now to determine the number of atoms, multiply by Avogadro's number. So
0.096702716 * 6.0221409x10^23 = 5.823574x10^22
Rounding to 4 significant figures, gives 5.824x10^22
