Final answer:
The number of sodium (Na) atoms in 310 grams of Na is approximately 8.11 × 10²´ atoms, calculated by first determining the number of moles from the mass and atomic mass of Na and then multiplying by Avogadro's number.
Step-by-step explanation:
To determine the number of sodium (Na) atoms in 310 grams of Na, we need to use Avogadro's number, which is 6.022 × 10²³ atoms per mole. First, we calculate the number of moles of sodium in 310 grams using its atomic mass, which is approximately 23.0 u (atomic mass units).
Number of moles of Na = Mass of Na (in grams) / Atomic mass of Na (in amu) = 310 g / 23.0 g/mol
Calculating the moles we get roughly 13.4783 moles of Na.
Next, we use Avogadro's number to find the number of atoms:
Number of atoms = Number of moles × Avogadro's number = 13.4783 moles × 6.022 × 10²³ atoms/mole
This gives us approximately 8.11 × 10²´ sodium atoms, which corresponds to answer choice B.