From the electronic configurations N (2,5), O (2,6) and F (2,7), answer the following questions:
What is the period number of O in the periodic table?

Explanation

To determine the period number of oxygen (O) in the periodic table based on its electronic configuration, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Electronic Configuration**:
The electronic configuration of oxygen (O) is given as 2,6. This means that oxygen has 2 electrons in the first shell (K shell) and 6 electrons in the second shell (L shell).

2. **Determine the Number of Electron Shells**:
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