Period to which copper belongs

Options

A. 6th
B. 3rd
C. 5th
D. 4th

Answer

To determine the period to which copper belongs, we can follow these steps:

### Step 1: Identify the Atomic Number of Copper
Copper has the atomic number 27. This means it has 27 protons and, in a neutral atom, also 27 electrons.

### Step 2: Write the Electronic Configuration of Copper
The electronic configuration of copper (Cu) can be written as:
\[ \text{Cu: } [\text{Ar}] 3d^{10} 4s^1 \]
Where [Ar] represents the electron configuration of Argon, which is the noble gas preceding copper in the periodic table.

### Step 3: Determine the Valence Electrons
The valence electrons are the electrons in the outermost shell. In the case of copper, the outermost shell is the 4th shell, which contains:
- 1 electron in the 4s subshell
- 10 electrons in the 3d subshell (though these are technically not in the outermost shell, they are involved in bonding)

### Step 4: Identify the Principal Quantum Number
The principal quantum number (n) corresponds to the highest energy level that has electrons. For copper, the highest energy level with electrons is 4 (from the 4s subshell).

### Step 5: Determine the Period
The period of an element in the periodic table is determined by the principal quantum number of its valence electrons. Since the principal quantum number for copper's valence electron is 4, copper belongs to the 4th period of the periodic table.

### Conclusion
Thus, copper belongs to the 4th period of the periodic table.

### Final Answer
Copper belongs to the 4th period of the periodic table.

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