Explain the formation of ionic bond in Ca and Cl atoms.

Answer

To explain the formation of an ionic bond between calcium (Ca) and chlorine (Cl) atoms, we can break it down into several steps:

### Step 1: Understanding the Electron Configuration
- **Calcium (Ca)** has an atomic number of 20. Its electron configuration is \(1s^2 2s^2 2p^6 3s^2\). The outermost shell (valence shell) has 2 electrons in the 3s subshell.
- **Chlorine (Cl)** has an atomic number of 17. Its electron configuration is \(1s^2 2s^2 2p^6 3s^2 3p^5\). The outermost shell has 7 electrons (2 in 3s and 5 in 3p).

### Step 2: Determining the Need for Electron Transfer
- Calcium, having 2 electrons in its outermost shell, tends to lose these 2 electrons to achieve a stable electron configuration (similar to the nearest noble gas, Argon).
- Chlorine, with 7 electrons in its outermost shell, needs 1 more electron to complete its octet and achieve stability (similar to the nearest noble gas, Argon).

### Step 3: Electron Transfer
- Calcium loses 2 electrons, becoming a positively charged ion (cation):
\[ \text{Ca} \rightarrow \text{Ca}^{2+} + 2e^- \]
- Each chlorine atom accepts 1 electron to complete its octet, becoming negatively charged ions (anions):
\[ \text{Cl} + e^- \rightarrow \text{Cl}^- \]
- Since 2 electrons are lost by calcium, 2 chlorine atoms are needed to accept these electrons:
\[ 2 \text{Cl} + 2e^- \rightarrow 2 \text{Cl}^- \]

### Step 4: Formation of Ionic Compound
- The resulting ions are \( \text{Ca}^{2+} \) and \( 2 \text{Cl}^- \).
- The formula for the ionic compound formed is:
\[ \text{CaCl}_2 \]
- The ionic bond is formed due to the electrostatic attraction between the positively charged calcium ion and the negatively charged chloride ions.

### Step 5: Conclusion
- The ionic bond in \( \text{CaCl}_2 \) is a result of the transfer of electrons from calcium to chlorine, leading to the formation of cations and anions that are held together by strong electrostatic forces.

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