The number of electrons in the valence shell of an element of atomic number 14 is?

1. Analyze the question

The question asks for the number of electrons in the outermost shell (valence shell) of an element with an atomic number of 14.

2. Explain the concept

To find the valence electrons, we must determine the electronic configuration of the element. The electronic configuration shows how electrons are distributed in the shells (K, L, M, N...).

• The first shell (K) holds a maximum of 2 electrons.
• The second shell (L) holds a maximum of 8 electrons.
• The third shell (M) holds the remaining electrons.

The valence shell is the outermost shell of an atom, and the electrons residing in this shell are called valence electrons.

3. Show the solution

• Step 1: Identify the atomic number. The atomic number is 14. This means there are 14 electrons to distribute.
• Step 2: Distribute the electrons into shells: • 1st shell (K): 2 electrons • 2nd shell (L): 8 electrons • Total used so far: $2 + 8 = 10$ electrons. • Remaining electrons: $14 - 10 = 4$ electrons.
• Step 3: Place the remaining electrons in the 3rd shell (M): • 3rd shell (M): 4 electrons.
• Step 4: The electronic configuration is 2, 8, 4. Since the outermost shell is the 3rd shell, it contains 4 electrons.

4. Identify the answer

The number of electrons in the valence shell is 4. This corresponds to option D.

5. Tip

To quickly find the valence electrons for elements in the main groups (Groups 1–8), look at the last digit of the electronic configuration. For example, if an element has 15 electrons (2, 8, 5), it has 5 valence electrons and belongs to Group 5. Remember, the valence electrons determine the chemical properties and the group number of the element!