Question

Number of elements presents in the fifth period of periodic table is:

• A. 32
• B. 10
• C. 18
• D. 8

Answer 1

Answer: (C)

18

The fifth period contains 18 elements beginning with rubidium and ending with xenon. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order; however, there are exceptions, such as rhodium.

Hence, option C is correct.