How many periods and groups are there in the modern periodic table ?

Explanation

To answer the question "How many periods and groups are there in the modern periodic table?", we can break it down into clear steps.

### Step-by-Step Solution:

1. **Understanding the Structure of the Periodic Table**:
- The periodic table is organized into vertical columns called **groups** and horizontal rows called **periods**.

2. **Counting the Groups**:
...