$ (a)\;\text{decreases (i) From left to right across a period and (ii) on descending a group} \\(b)\;\text {decreases from left to right across a period and increases on descending a group} \\ (c)\;\text {increases from left to right across a period and descending a groups} \\ (d)\;\text {decreases (i) From left to right across a period and (ii) on descending a group} $
