How many `Cl^(-)` ions are there around `Na^(+)`ion in NaCl crystal ?

Options

A. 3
B. 4
C. 6
D. 8

Answer

To determine how many chloride ions (Cl^(-)) are around a sodium ion (Na^(+)) in an NaCl crystal, we can follow these steps:

### Step 1: Understand the Structure of NaCl
NaCl crystallizes in a face-centered cubic (FCC) structure, also known as the rock salt structure. In this structure, sodium ions (Na^(+)) and chloride ions (Cl^(-)) alternate in a three-dimensional lattice.

**Hint:** Remember that NaCl has a specific crystal structure that influences how ions are arranged.

### Step 2: Identify the Coordination Number
The coordination number of an ion in a crystal lattice is the number of nearest neighboring ions surrounding it. For NaCl, the coordination number for both Na^(+) and Cl^(-) is 6. This means each Na^(+) ion is surrounded by 6 Cl^(-) ions.

**Hint:** The coordination number indicates how many ions are directly adjacent to a given ion.

### Step 3: Visualize the Arrangement
In the FCC lattice, the Na^(+) ions occupy the octahedral voids. Each Na^(+) ion is located at the center of an octahedron formed by 6 Cl^(-) ions. The Cl^(-) ions are located at the corners and the face centers of the cube.

**Hint:** Visualizing the arrangement can help you understand how ions interact in the crystal lattice.

### Step 4: Count the Cl^(-) Ions Surrounding Na^(+)
Since each Na^(+) ion is surrounded by 6 Cl^(-) ions, we can conclude that there are 6 chloride ions around each sodium ion in the NaCl crystal.

**Hint:** Focus on the immediate neighbors to determine how many ions surround the central ion.

### Final Answer
There are **6 Cl^(-) ions** around each Na^(+) ion in an NaCl crystal.