How many valence electrons does a neutral atom of aluminum have?
The correct answer and explanation is:
A neutral atom of aluminum has 3 valence electrons.
Aluminum is located in Group 13 of the periodic table, which indicates that it has 3 valence electrons. The valence electrons are the electrons in the outermost shell of an atom that are involved in chemical bonding. In the case of aluminum, its electron configuration is 1s² 2s² 2p⁶ 3s² 3p¹. The first two electron shells are filled with 2 and 8 electrons, respectively, while the third shell contains 3 electrons in total (2 in the 3s orbital and 1 in the 3p orbital).
Valence electrons determine an atom’s chemical reactivity and its ability to form bonds with other atoms. Since aluminum has 3 electrons in its outermost shell, it can lose these 3 electrons in a chemical reaction, forming a positive ion (Al³⁺) with a stable electron configuration. This tendency to lose electrons is why aluminum is a metal and why it typically forms ionic bonds, especially with elements like chlorine to form aluminum chloride (AlCl₃).
In summary, the number of valence electrons in an atom corresponds to its group number in the periodic table. For aluminum, its placement in Group 13 means it has 3 valence electrons, making it capable of losing those electrons in chemical reactions to form positive ions. This property of aluminum is key to its behavior in various chemical processes, including those in metallurgy and material science.