Which one among the following elements has the lowest first ionisation enthalpy and which of the has highest first ionisation enthalpy ? Li, K , Ca , S and Kr.

Explanation

To determine which element has the lowest and highest first ionization enthalpy among Li, K, Ca, S, and Kr, we can follow these steps:

### Step 1: Understand Ionization Enthalpy
First, we need to understand what first ionization enthalpy means. It is the energy required to remove the most loosely bound electron from a neutral atom in its gaseous state.

### Step 2: Identify the Position of Elements in the Periodic Table
Next, we will identify the positions of the given elements in the periodic table:
- **Li (Lithium)**: Group 1, Period 2
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