The order in which the following oxides are arranged according to decreasing basic nature is

Options

A. `Na_(2)O, MgO, Al_(2)O_(3), CuO`
B. `CuO, Al_(2)O_(3), MgO, Na_(2)O`
C. `Al_(2)O_(3), CuO, MgO, Na_(2)O`
D. `CuO, MgO, Na_(2), Al_(2)O_(3)`

Answer

To determine the order of the given oxides according to their decreasing basic nature, we can follow these steps:

### Step 1: Identify the Oxides
We need to identify the oxides provided in the question. Let's assume the oxides are:
1. Na2O (Sodium oxide)
2. MgO (Magnesium oxide)
3. Al2O3 (Aluminum oxide)
4. CuO (Copper(II) oxide)

### Step 2: Understand Basic Nature of Oxides
Metallic oxides are generally basic in nature, while non-metallic oxides tend to be acidic. The basic nature of oxides decreases as we move from left to right across a period in the periodic table due to the increasing non-metallic character.

### Step 3: Analyze the Oxides
- **Na2O**: Sodium is an alkali metal and forms a strongly basic oxide.
- **MgO**: Magnesium is an alkaline earth metal, and its oxide is also basic but less so than Na2O.
- **Al2O3**: Aluminum oxide is amphoteric, meaning it can act as both an acid and a base, but it is less basic than Na2O and MgO.
- **CuO**: Copper is a transition metal, and its oxide is more acidic compared to the others listed.

### Step 4: Arrange the Oxides
Based on the analysis:
1. **Na2O** - Most basic
2. **MgO** - Second most basic
3. **Al2O3** - Less basic (amphoteric)
4. **CuO** - Least basic

### Final Order
Thus, the order of the oxides according to decreasing basic nature is:
**Na2O > MgO > Al2O3 > CuO**