Among the given statements, the incorrect one is

Options

A. Be differs much from other alkali metals than `Li` does from other alkali metals.
B. Be generally forms covalent compounds.
C. Be forms a very strong complex, `[Be(H_(2)O)_(4)]^(2+)`.
D. Be usually has more than four water of crystallisation associated with it.

Explanation

To determine which statement among the given options is incorrect, we need to analyze the properties of alkali metals and alkaline earth metals, particularly focusing on lithium and beryllium.

### Step-by-Step Solution:

1. **Identify the Groups**:
- Alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).
- Alkaline earth metals include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

2. **Compare Lithium and Beryllium**:
- Both lithium and beryllium are the first elements in their respective groups. They have smaller atomic sizes compared to other elements in their groups.
- Due to their small size and high polarizing power, both lithium and beryllium exhibit different properties compared to the other elements in their groups.

3. **Examine the Statements**:
- The first statement claims that "beryllium differs much from other alkali metals than lithium does from alkali metals." This statement is incorrect because beryllium is not an alkali metal; it is an alkaline earth metal. Therefore, it cannot be compared to alkali metals directly.

4. **Covalent Compounds**:
- Both beryllium and lithium tend to form covalent compounds due to their small size and high polarizing power. For example, beryllium chloride (BeCl2) is a covalent compound.

5. **Complex Formation**:
- Beryllium can form complexes, such as tetra-aqua beryllium, due to its ability to accommodate lone pairs from water molecules.

6. **Conclusion**:
- The incorrect statement is the one that compares beryllium to alkali metals, as beryllium belongs to the alkaline earth metals group.

### Final Answer:
The incorrect statement is: "Beryllium differs much from other alkali metals than lithium does from alkali metals."

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