Final answer:
The mass ratio of Na to I in sodium iodide is found by dividing the atomic mass of Na (23.0 amu) by the atomic mass of I (127.0 amu), yielding a ratio of 0.181, which corresponds to option A.
Step-by-step explanation:
To find the mass ratio of Na to I in sodium iodide (NaI), we need to use the atomic masses of sodium (Na) and iodine (I). The relative atomic mass of sodium is approximately 23.0 amu, and the relative atomic mass of iodine is approximately 127.0 amu. The mass ratio of Na to I is calculated by dividing the atomic mass of Na by that of I:
Mass ratio (Na:I) = Atomic mass of Na / Atomic mass of I = 23.0 / 127.0 = 0.181.
Thus, the correct answer is A. 0.181. This shows the ratio of the mass of sodium to the mass of iodine in sodium iodide.