[" 17.The edge length of a face centred cubic cell of an ionic "],[" substance is "508pm" .If the radius of the cation is "110pm" ,"],[" the radius of the anion is: "],[[" (a) "144pm," (b) "288pm],[" (c) "398pm," (d) "618pm" (AIEEE "2010)],[" 18In a face centred cubic lattice,atom A occupies the corner "]]