WAEC - Chemistry (1989 - No. 29)
The electronic configuration of two atoms X and Y are as follows: X - 1s 2 2s 22p 63s 1, Y -1s 22s 22p 63s23p 64s 2 which of the statements below is true of the position of X and Y in the Periodic Table?
x belongs to group 1, Y belongs to period 2,
x belongs to group 1, Y belongs to period 4
x belongs to group 2, Y belongs to period 1
x belongs to group 3, Y belongs to period 2
x belongs to group 3, Y belongs to period 4