Question

A certain oxygen atom has the electron configuration 1\(s^{2} 2 s^{2} 2 p_{x}^{2} 2 p_{y}^{2} .\) How many unpaired electrons are present? Is this an excited state of oxygen? In going from this state to the ground state, would energy be released or absorbed?

Short answer

The given electron configuration (\(1s^2 2s^2 2p_x^2 2p_y^2\)) represents an excited state of an oxygen atom with no unpaired electrons. When transitioning to the ground state of oxygen (\(1s^2 2s^2 2p^4\)), energy will be released.

Step-by-step solution

Analyze Electron Configuration

The given electron configuration for the oxygen atom is \(1s^2 2s^2 2p_x^2 2p_y^2\). This tells us that the oxygen atom has two electrons in the 1s orbital, two electrons in the 2s orbital, and two electrons each in the 2p_x and 2p_y orbitals.

Calculate the Number of Unpaired Electrons

In order to calculate the number of unpaired electrons, we must analyze the electron configuration of the oxygen atom. Since all the electrons in the 1s and 2s orbitals are paired, there are no unpaired electrons within those orbitals. Furthermore, the 2p_x and 2p_y orbitals both have two electrons, indicating that all electrons are paired. Therefore, there are 0 unpaired electrons in this configuration.

Determine if this is an Excited State of Oxygen

The ground state electron configuration of an oxygen atom is \(1s^2 2s^2 2p^4\). In comparison to the given electron configuration \(1s^2 2s^2 2p_x^2 2p_y^2\), we see that there is a discrepancy in the 2p orbitals. Oxygen should have two unpaired electrons in its 2p orbital, while the given configuration has all electrons paired in the 2p_x and 2p_y orbitals. This indicates that the given configuration is an excited state of the oxygen atom.

Determine if Energy is Released or Absorbed in Going to the Ground State

When an atom transitions from an excited state to the ground state, energy is released in the form of a photon. In the given configuration, the oxygen atom needs to go from its excited state to the ground state to achieve stability. As a result, energy will be released in the transition from the given electron configuration to the ground state configuration. In conclusion, the given electron configuration represents an excited state of an oxygen atom with 0 unpaired electrons. When transitioning to the ground state, the oxygen atom would release energy.

Key concepts

Unpaired Electrons

In understanding electron configurations, one crucial aspect is the concept of unpaired electrons. These are electrons that reside alone in an orbital when filling up the subshells according to the Pauli exclusion principle and Hund's rule. Having unpaired electrons is significant as it contributes to magnetic properties and reactivity of the atom.

In our exercise, we have an oxygen atom with the electron configuration:

• 1\(s^2\) 2\(s^2\) 2\(p_x^2\) 2\(p_y^2\).

To determine the number of unpaired electrons, we analyze the 2p orbitals. Normally, in the ground state, oxygen's 2p subshell should fill as \(2p_x^2\) \(2p_y^1\) \(2p_z^1\), with two unpaired electrons in the 2p subshell. However, here, our 2p subshell shows \(2p_x^2\) and \(2p_y^2\), leaving no electrons in the \(2p_z\) orbital. Consequently, all electrons are paired. Hence, this configuration has 0 unpaired electrons.

Excited State

Atoms can have electrons in excited states if they are given energy to jump to higher energy levels or occupy orbitals out of the usual order. The excited state contrasts with the ground state, which represents the lowest energy, most stable configuration of an atom.

The ground state electron configuration for oxygen is:

• 1\(s^2\) 2\(s^2\) 2\(p^4\)

This should be represented as \(2p_x^2\) \(2p_y^1\) \(2p_z^1\), with two orbitals having unpaired electrons.

In the given configuration \(2p_x^2\) \(2p_y^2\), all 2p electrons are paired, which is not characteristic of oxygen in its ground state. This occupied structure uses a different electron distribution from the ground state, indicating an excited state. Excited states often arise when atoms have absorbed energy, causing electrons to occupy higher or different orbital arrangements.

Ground State Transition

Transitioning from an excited state to a lower energy state or the ground state typically involves energy changes. When electrons "relax" back to the ground state, they release energy, often in the form of a photon.

For the oxygen atom transitioning from the given excited state \(1s^2 2s^2 2p_x^2 2p_y^2\) back to its ground state configuration, the previously absorbed energy in the higher configuration \((excited state)\) is released.

The process of energy release can be represented by:

• \(\text{Excited state} \rightarrow \text{Ground state} + \text{Photon (energy) released}\)

Thus, when the electrons in oxygen rearrange from the given state to ground state configuration, energy will be emitted, stabilizing the atom.