Question

How many periods are there in the periodic table ?

• A. 12
• B. 9
• C. 8
• D. 7

Hint:

Remember the basic structure of the modern periodic table: 7 periods (rows) and 18 groups (columns).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The periodic table is organized into horizontal rows and vertical columns. The question asks for the number of horizontal rows.

Step 2: Detailed Explanation:
\[\begin{array}{rl} \bullet & \text{The horizontal rows in the periodic table are called periods.} \\ \bullet & \text{The vertical columns are called groups.} \\ \bullet & \text{In the modern periodic table, there are a total of 7 periods.} \\ \bullet & \text{The period number of an element signifies the principal energy level for its outermost electrons.} \\ \end{array}\]

Step 3: Final Answer:
There are 7 periods in the modern periodic table.