Which orbitals are filled with electrons in `3rd` period?

Explanation

To determine which orbitals are filled with electrons in the 3rd period, we can follow these steps:

### Step 1: Identify the 3rd Period Elements
The 3rd period of the periodic table includes the elements from sodium (Na, atomic number 11) to argon (Ar, atomic number 18).

### Step 2: Understand the Electron Configuration
The electron configuration describes how electrons are distributed among the various orbitals. For the 3rd period, we need to focus on the 3s and 3p orbitals.

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