What is the number of valence electrons in aluminum?
The correct answer and explanation is:
A neutral atom of aluminum has three valence electrons.
The number of valence electrons in an atom corresponds to the number of electrons in the outermost electron shell or energy level. For aluminum, the atomic number is 13, which means it has 13 electrons in total when neutral. The electron configuration of aluminum is:
1s22s22p63s23p11s^2 2s^2 2p^6 3s^2 3p^1
In this configuration, the first two electron shells are filled (1s and 2s), and the third shell contains three electrons (two in the 3s subshell and one in the 3p subshell). These three electrons in the outermost shell are known as the valence electrons.
Valence electrons play a crucial role in determining how an atom interacts with other atoms. They are involved in chemical bonding, such as ionic or covalent bonds, where atoms either share or transfer electrons. Since aluminum has three valence electrons, it typically forms three bonds in most of its compounds, often by losing these three electrons to form a +3 ion. This is why aluminum tends to have a +3 oxidation state in many of its compounds.
The number of valence electrons also determines the group number in the periodic table. Aluminum is in Group 13, which means all elements in this group have three valence electrons. This periodicity is part of why elements in the same group share similar chemical properties.