The ionic substance strontium oxide, SrO, forms from the reaction of strontium metal with molecular oxygen. The arrangement of the ions in solid SrO is analogous to that in solid NaCl:

(b) Based on the ionic radii in Figure 7.8, predict the length of the side of the cube in the figure (the distance from the center of an atom at one corner to the center of an atom at a neighboring corner).

Video transcript

Hi everyone here we have a question telling us that a portion of the potassium bromide lattice has shown below. And our goal is to calculate the length of the side of the cube based on the ionic red eye of each element. The radius of potassium and bromine is 1.52 angstrom and 1.82 angstrom respectively. Assume that the edge and corners of the cube are in the center of the atoms. So we have potassium Which is 1.52 Angstrom, which was given to us in the prompt. And we have browning, Which is 1.82 Angstrom. And assuming that the corner ends in the center of the atom means we only use one of the radius of the corner atoms and we use twice the radius for the inside atoms. So our top edge is browning potassium bromate, which means that we will use roaming plus two potassium plus browning. So 1.82 Angstrom Plus two times 1.52 Angstrom Plus 1.82 extremes And that equals 6.68 Angstrom. And that is our final answer. Thank you for watching. Bye