Show that the ideal c/a ratio (height of unit cell divided by edge length) for the HCP unit cell is 1.633. (You may wish to refer to Exercise E.2 in the text page GL 1-6) Comment on the fact that real HCP metals display c/a ratios varying from 1.58 (for Be) to 1.89 (Cd). The atomic radius of HCP Mg is 0.1605 nm. Find the lattice constants, c and a, the c/a ratio and theoretical density for Mg.

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?