How many valence electrons does nickel have?
The Correct Answer and Explanation is :
Nickel (Ni), with an atomic number of 28, has 2 valence electrons.
Explanation:
Valence electrons are the electrons in the outermost shell (energy level) of an atom that are involved in chemical bonding. To understand why nickel has 2 valence electrons, we need to examine its electron configuration.
Nickel’s electron configuration is as follows:
- First shell: 2 electrons (2s²)
- Second shell: 8 electrons (2p⁶, 3s²)
- Third shell: 8 electrons (3p⁶, 3d⁸)
- Fourth shell: 2 electrons (4s²)
The key to understanding the valence electrons of nickel lies in its position in the periodic table. Nickel is located in the transition metal block, specifically in Group 10 (the 10th column of the periodic table). For transition metals, the electrons in the outermost ss-orbitals and the dd-orbitals contribute to bonding.
In the case of nickel, the two electrons in the 4s orbital are the valence electrons. Although nickel also has electrons in its 3d orbital (3d⁸), these electrons are considered to be in the penultimate (second-to-last) shell and are not typically involved in chemical bonding in the same way as the outermost ss-orbital electrons.
Thus, the 2 valence electrons in the 4s orbital are the primary electrons involved in bonding for nickel. These electrons determine its chemical properties, including its tendency to form metallic bonds in its pure form and the type of compounds it forms with other elements.
In summary, nickel has 2 valence electrons, which are located in the 4s orbital.