The combination of atoms occur because they want

Options

A. to decrease number of electrons in the outermost orbit
B. to attain inert gas configuration
C. to increase number of electrons in the outermost orbit
D. to attain 18 electrons in the outermost orbit.

Explanation

### Step-by-Step Solution:

1. **Understanding Atomic Stability**: Atoms tend to combine to achieve a more stable electronic configuration. This stability is often associated with having a full outer shell of electrons, similar to the noble gases.

2. **Example of Sodium (Na)**: Sodium has an atomic number of 11, which gives it the electronic configuration of 1s² 2s² 2p⁶ 3s¹. This means it has one electron in its outermost shell (3s orbital). To achieve stability, sodium will lose this one electron.

3. **Formation of Sodium Ion (Na⁺)**: When sodium loses one electron, it becomes a positively charged ion (Na⁺). This loss of an electron allows sodium to attain the stable electronic configuration of neon, which is an inert gas.

4. **Example of Chlorine (Cl)**: Chlorine has an atomic number of 17, resulting in the electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁵. Chlorine has seven electrons in its outermost shell and needs one more electron to achieve a full outer shell (8 electrons), which is also the stable configuration of argon.

5. **Formation of Chloride Ion (Cl⁻)**: Chlorine will gain one electron to fill its outer shell, becoming a negatively charged ion (Cl⁻). This gain of an electron allows chlorine to achieve the stable electronic configuration of argon.

6. **Combination to Form NaCl**: When sodium (Na) and chlorine (Cl) come together, sodium donates its one electron to chlorine. This results in the formation of the ionic compound sodium chloride (NaCl). In this compound, Na⁺ and Cl⁻ are held together by electrostatic forces of attraction, forming a stable ionic bond.

7. **Conclusion**: The combination of atoms occurs because they want to attain a stable electronic configuration, similar to that of inert gases. This drive for stability through electron transfer leads to the formation of compounds like NaCl.