How many elements are present in the fifth period of the modern periodic table?

The horizontal rows of the periodic table are called periods. There are 7 periods. The first period contains 2  elements, the second and third contain 8 elements, the fourth and fifth contain 18 elements and the sixth contains 32 elements. The seventh period contains 19 elements till now.

The members of the fifth period are  Rubidium, Strontium, Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver, Cadmium, Indium, Tin, Antimony, Tellurium, Iodine and Xenon.