What is the total number of electron present in the last orbit of argon?

Explanation

To determine the total number of electrons present in the last orbit of argon, we can follow these steps:

### Step 1: Identify the Atomic Number of Argon
The atomic number of argon (Ar) is 18. This means that argon has 18 electrons in total.

### Step 2: Write the Electronic Configuration
The electronic configuration of argon can be derived from its atomic number. The configuration is:
- 1s² 2s² 2p⁶ 3s² 3p⁶

### Step 3: Identify the Last Orbit
In the electronic configuration:
- The first shell (K shell) contains 1s²
- The second shell (L shell) contains 2s² 2p⁶
- The third shell (M shell) contains 3s² 3p⁶

The last orbit (or valence shell) for argon is the third shell, which includes the 3s and 3p subshells.

### Step 4: Count the Electrons in the Last Orbit
In the last orbit (3rd shell):
- The 3s subshell has 2 electrons.
- The 3p subshell has 6 electrons.

### Step 5: Calculate the Total Electrons in the Last Orbit
To find the total number of electrons in the last orbit, we add the electrons from the 3s and 3p subshells:
- Total electrons = 2 (from 3s) + 6 (from 3p) = 8 electrons.

### Final Answer
The total number of electrons present in the last orbit of argon is **8 electrons**.

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