Answer the following:
Give the name of the hardest alakli metal.

Explanation

To answer the question, "Give the name of the hardest alkali metal," we can follow these steps:

### Step-by-Step Solution:

1. **Identify Alkali Metals**: Alkali metals are found in Group 1 of the periodic table. They include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

2. **Understand the Properties of Alkali Metals**: Alkali metals have a single electron in their outermost shell (valence shell), which is in the s sub-shell (NS1 configuration). This configuration leads to certain trends in their physical properties.

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