How many electrons are there in the valence quantum level of copper (atomic number = 29) atom ? Give reasons.

Explanation

To determine the number of electrons in the valence quantum level of a copper atom (atomic number = 29), we can follow these steps:

### Step 1: Identify the Atomic Number
The atomic number of copper is given as 29. This indicates that a neutral copper atom has 29 electrons.

### Step 2: Write the Electronic Configuration
The electronic configuration of copper can be derived based on the Aufbau principle, Hund's rule, and the Pauli exclusion principle. For copper, the expected electronic configuration would be:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁹
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