Question

The number of elements present in the fifth period of the modern periodic table:

• A. 8
• B. 10
• C. 18
• D. 32

Hint:

Each period in the periodic table contains a specific number of elements, and the fifth period contains 18 elements.

Answer 1

The Correct Option is C

Step 1: Definition of Period.
A period in the periodic table refers to a horizontal row of elements, which contains a set number of elements depending on the electron configuration and the number of available orbitals. Step 2: Elements in the Fifth Period.
The fifth period contains the following elements: \[ \text{K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr} \] These elements range from potassium (K) to krypton (Kr), totaling 18 elements. Step 3: Conclusion.
Hence, there are 18 elements in the fifth period of the modern periodic table.