Answer:
Since element X is in period 2, it is a member of the second row (or period) of the periodic table of elements. The second period contains the elements Li, Be, B, C, N, O, F, and Ne. Therefore, the chemical symbol for element X could be any of these elements.
Since element Y is in period 1, it is a member of the first row (or period) of the periodic table of elements. The first period contains only two elements, H (Hydrogen) and He (Helium). Therefore, the chemical symbol for element Y could be either H or He.