How many valence electrons does an iron atom (Fe) have? Select the correct answer below:
a. 8
b. 6
c. 4
d. 2
The Correct Answer and Explanation is :
The correct answer is d. 2.
Explanation:
Iron (Fe) is an element located in the transition metals group of the periodic table, with an atomic number of 26. This means that an iron atom has 26 electrons, which are arranged in various electron shells around the nucleus. To determine how many valence electrons iron has, we must first understand the electron configuration of the atom.
The electron configuration of iron (Fe) is:
Fe: [Ar] 3d^6 4s^2
This means that the first 18 electrons fill up the inner shells and are represented by the argon (Ar) core configuration, which is stable and non-reactive. The remaining 8 electrons (26 – 18 = 8) are distributed across the 3d and 4s orbitals.
- The 4s orbital contains 2 electrons, and
- The 3d orbital contains 6 electrons.
In chemistry, valence electrons are those electrons that are found in the outermost shell and can participate in chemical bonding. For transition metals like iron, the electrons in both the 4s orbital and the 3d orbital are considered to be valence electrons because these electrons can be involved in forming bonds with other atoms.
Although iron has 8 outer electrons in total (2 from 4s and 6 from 3d), in many chemical reactions, iron tends to lose 2 electrons from the 4s orbital first, which gives it a typical valence of 2+. Therefore, when we discuss the typical valence for iron, we refer to 2 valence electrons.
This is why the correct answer is d. 2. Iron can also form other oxidation states, such as +3, by losing additional electrons, but 2 is the most common in its simple ionic form.
Let me generate an image showing the electron configuration and valence electrons of iron!
Here is the diagram showing the electron configuration of an iron (Fe) atom, highlighting the 2 valence electrons in the 4s orbital and the 6 valence electrons in the 3d orbital. This visual should help you understand how the valence electrons are distributed.