Silicon is the second most abundant element `(~27.2%)` in the earth's after oxygen `(45.5 %)` Carbon. Silicon, germanium, tin and lead constitute the group `14` of the periodic table. Chemistry of silicon is distinctly different from that of carbon.
For example, under standard conditions `CO_(2)` is a gas whereas `SiO_(2)` is a covalent solid.
Group `14` elements have tendency to catenate. The first three members `C, Si` and `Ge` show significant catenation. Arrange these elements in decreasing order of their catenation tendency.

Answer

To arrange the elements carbon (C), silicon (Si), and germanium (Ge) in decreasing order of their catenation tendency, we need to understand the concept of catenation and the bond energies associated with each element.

### Step-by-Step Solution:

1. **Understand Catenation**:
- Catenation is the ability of an element to form chains or large structures by bonding with itself. This property is significant in elements like carbon, silicon, and germanium.

2. **Identify the Elements**:
- The elements in question are carbon (C), silicon (Si), and germanium (Ge), which are all part of group 14 in the periodic table.

3. **Examine Bond Energies**:
- The tendency to catenate is influenced by the bond energy of the element's bonds with itself. Higher bond energy generally indicates a greater tendency for catenation.
- The bond energies for the relevant bonds are:
- Carbon-Carbon (C-C) bond energy: 348 kJ/mol
- Silicon-Silicon (Si-Si) bond energy: 180 kJ/mol
- Germanium-Germanium (Ge-Ge) bond energy: 167 kJ/mol

4. **Compare Bond Energies**:
- From the bond energy values, we can see:
- C-C bond has the highest bond energy (348 kJ/mol).
- Si-Si bond has a lower bond energy (180 kJ/mol).
- Ge-Ge bond has the lowest bond energy (167 kJ/mol).

5. **Determine Catenation Tendency**:
- Since carbon has the highest bond energy, it has the greatest tendency to catenate.
- Silicon, with a lower bond energy than carbon but higher than germanium, has a moderate tendency to catenate.
- Germanium, with the lowest bond energy, has the least tendency to catenate.

6. **Arrange in Decreasing Order**:
- Based on the analysis, the order of catenation tendency from highest to lowest is:
- Carbon (C) > Silicon (Si) > Germanium (Ge)

### Final Answer:
**The decreasing order of catenation tendency is: Carbon (C) > Silicon (Si) > Germanium (Ge)**.