Which of the following is not a characteristic of alkali metals ?

Options

A. Low IE
B. Low EN
C. Ions are isoelectronic with noble gases
D. High EN

Explanation

To determine which of the following is not a characteristic of alkali metals, we need to analyze the given options based on the known properties of alkali metals.

### Step-by-Step Solution:

1. **Identify the Group of Alkali Metals:**
Alkali metals belong to Group 1 of the periodic table. They include elements like lithium (Li), sodium (Na), potassium (K), etc.

2. **Understand the General Electronic Configuration:**
Alkali metals have a general electronic configuration of \( ns^1 \), where \( n \) represents the principal quantum number. This configuration indicates that they have one electron in their outermost shell.

3. **Evaluate Ionization Energy:**
Alkali metals have the lowest ionization energy among all the elements in the periodic table. This is because they have larger atomic sizes, making it easier to lose the outermost electron. Therefore, the statement regarding low ionization energy is a characteristic of alkali metals.

4. **Assess Electronegativity:**
Alkali metals have low electronegativity values. Electronegativity is the tendency of an atom to attract electrons. Since alkali metals tend to lose electrons rather than gain them, they exhibit low electronegativity. Thus, this statement is also a characteristic of alkali metals.

5. **Check Isoelectronic Nature with Noble Gases:**
When alkali metals lose one electron, they form cations (e.g., \( Li^+, Na^+ \)), which have the same electronic configuration as the nearest noble gas. This means that alkali metal ions are isoelectronic with noble gases, making this statement a characteristic of alkali metals as well.

6. **Identify the Incorrect Characteristic:**
The question asks for the option that is not a characteristic of alkali metals. Since the first three statements are indeed characteristics, the fourth option, which likely states something contrary to the established properties of alkali metals (like having high electronegativity), is the correct answer.

### Conclusion:
The correct answer is **Option D**, as it does not represent a characteristic of alkali metals.

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