The number of valence electrons in `""_4X^8` atom is

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine the number of valence electrons in the atom represented by `""_4X^8`, we can follow these steps:

### Step 1: Identify the Atomic Number
The notation `""_4X^8` indicates that the atomic number (the number at the bottom) is 4. This means we are dealing with the element that has an atomic number of 4.

### Step 2: Identify the Element
The element with atomic number 4 is Beryllium (Be).

### Step 3: Determine the Electron Configuration
Next, we need to find the electron configuration of Beryllium. Beryllium has 4 electrons, and its electron configuration can be written as:
- 2 electrons in the first shell (K shell)
- 2 electrons in the second shell (L shell)

So, the electron configuration of Beryllium is:
- K shell: 2 electrons
- L shell: 2 electrons

### Step 4: Identify the Valence Shell
The valence shell is the outermost shell of an atom that contains electrons. For Beryllium, the outermost shell is the L shell.

### Step 5: Count the Valence Electrons
In the L shell, there are 2 electrons. Therefore, the number of valence electrons in a Beryllium atom is 2.

### Final Answer
The number of valence electrons in `""_4X^8` (Beryllium) is **2**.

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