Nacl is a compound that forms a rock salt structure (unit cell at right). the radius of the na+ atoms is 1.16 ǻ; the radius of the cl-atoms is 1.67 ǻ. (1ǻ = 10-10 m). use this information to answer the following questions: a. (2 pts.) how many nearest neighbor ions does each na+ and cl-ion have? b. (4 pts.) calculate the lattice parameter of nacl. c. (6 pts.) sketch the (100) of nacl, as close to scale as possible. use the same color scheme (white and dark) as the model to indicate which atoms are na+ and cl-.