Question

Discuss the formation of an ionic bond between zinc and oxygen

Short answer

The formation of an ionic bond between zinc and oxygen begins with their electronic configurations, which are \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^10\) for zinc, and \(1s^2 \ 2s^2 \ 2p^4\) for oxygen. Zinc loses two electrons from its \(4s^2\) orbital, forming a \(Zn^{2+}\) ion, while oxygen gains two electrons to fill its \(2p\) orbital, forming an \(O^{2-}\) ion. The electrostatic force between the positively charged \(Zn^{2+}\) ion and the negatively charged \(O^{2-}\) ion results in the formation of an ionic bond, creating the ionic compound zinc oxide (ZnO).

Step-by-step solution

Determine the electronic configuration of zinc and oxygen

To understand how an ionic bond forms between zinc and oxygen, we need to look at their respective electronic configurations. Zinc (Zn) has an atomic number of 30 and its electronic configuration is \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^10\). Oxygen (O) has an atomic number of 8 and its electronic configuration is \(1s^2 \ 2s^2 \ 2p^4\).

Loss/gain of electrons to form ions

Both elements will try to achieve a stable electronic configuration by having a full outer electron shell. In this case, zinc can lose two electrons from its \(4s^2\) orbital, forming a \(Zn^{2+}\) ion with an electronic configuration of \(1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 3d^{10}\). Oxygen, on the other hand, can gain two electrons to fill its \(2p\) orbital, forming an \(O^{2-}\) ion with an electronic configuration of \(1s^2 \ 2s^2 \ 2p^6\).

Formation of an ionic bond between zinc and oxygen

The positively charged zinc ion (\(Zn^{2+}\)) and the negatively charged oxygen ion (\(O^{2-}\)) are attracted to each other due to the electrostatic force between them. This attractive force leads to the formation of an ionic bond between zinc and oxygen, resulting in the formation of the ionic compound zinc oxide (ZnO).

Key concepts

Zinc Electron Configuration

Understanding the electron configuration of zinc is important when discussing how it forms an ionic bond. Zinc has an atomic number of 30, indicating that it has 30 electrons in its neutral state. The configuration of these electrons follows a specific order based on energy levels: \(1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10}\). The outermost electrons, which are in the \(4s^2\) subshell, are the ones that play a key role in bonding.

When zinc forms an ionic bond, it typically loses the two electrons in the \(4s^2\) subshell. This loss allows zinc to achieve a more stable electronic structure, resembling that of a noble gas. After losing these two electrons, zinc becomes a \(Zn^{2+}\) ion, now having the configuration \(1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^{10}\). By shedding these electrons, zinc meets the guideline of having a filled d-subshell, which provides stability.

This electron loss is key in forming ionic compounds and shows why zinc often appears as \(Zn^{2+}\) in chemical reactions.

Oxygen Electron Configuration

Oxygen’s electron configuration is critical in understanding how it participates in ionic bonding. Oxygen, with an atomic number of 8, has 8 electrons in a neutral atom. These electrons are arranged in the configuration \(1s^2 \, 2s^2 \, 2p^4\). The main point to note here is that the \(2p\) subshell contains four electrons, but it has a capacity to hold six.

When oxygen engages in forming an ionic compound, it aims to fill this \(2p\) subshell completely. By gaining two additional electrons, oxygen achieves a full octet, matching the stable electron arrangement of neon, a noble gas with a configuration of \(1s^2 \, 2s^2 \, 2p^6\). This gain leads to the formation of the \(O^{2-}\) ion.

• This ion is negatively charged because it has two extra electrons compared to a neutral oxygen atom.
• The full octet provides stability, making \(O^{2-}\) ions prevalent in oxygen's chemical bonding behavior.

These additional electrons and the resulting radial electron arrangement make oxygen an ideal candidate for forming ionic bonds with metals, like zinc.

Ionic Compounds

Ionic compounds are formed when metals react with nonmetals, and they are held together by ionic bonds. In the case of zinc and oxygen, when they form zinc oxide, they do so by transferring electrons.

Here's the process simplified:

• Zinc, being a metal, loses two electrons, forming a \(Zn^{2+}\) ion.
• Oxygen, a nonmetal, gains these two electrons, forming an \(O^{2-}\) ion.
• These ions are then attracted to each other through electrostatic forces, which is the basis of their ionic bond.

The result of this electron exchange is the formation of an ionic compound, in this case, zinc oxide (ZnO). Ionic compounds typically have high melting and boiling points, due to the strong attraction between the ions.

Moreover, they can conduct electricity when dissolved in water or melted because the ions are free to move around. Understanding the nature of ionic compounds is essential for recognizing their role and behavior in various chemical reactions and applications.