Question

Consider the following statement: "The ionization energy for the potassium atom is negative, because when K loses an electron to become \(\mathbf{K}^{+}\), it achieves a noble gas electron configuration" Indicate everything that is correct in this statement. Indicate everything that is incorrect. Correct the incorrect information and explain.

Short answer

The correct part of the statement is that when potassium loses an electron to become \(K^{+}\), it achieves a noble gas electron configuration, similar to Argon. However, the incorrect part is that the ionization energy for potassium is negative. Ionization energy is always positive, as it represents the energy required to remove an electron from an atom. The correct statement should be: "The ionization energy for the potassium atom is positive, because when K loses an electron to become \(K^{+}\), it achieves a noble gas electron configuration."

Step-by-step solution

Understand the concept of ionization energy

Ionization energy is the energy required to remove an electron from an atom or ion in the gas phase. It is an important property and usually increases as we move from left to right across a period and decreases as we move down a group in the periodic table.

Identify the correct parts of the statement

In the given statement, it is mentioned that when potassium loses an electron to become \(K^{+}\), it achieves a noble gas electron configuration. This is correct. Potassium has an electron configuration of \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1\), and upon losing one electron from the 4s orbital, it becomes \(K^{+}\) with the electron configuration \(1s^2 2s^2 2p^6 3s^2 3p^6\), which is similar to the noble gas Argon.

Identify the incorrect parts of the statement

The incorrect part of the statement is that the ionization energy for the potassium atom is negative. Ionization energy is always positive because energy is required to remove an electron from an atom or ion. The misconception might have arisen due to the negative value of electron affinity, which is the energy change associated with the addition of an electron to an atom or ion in the gas phase.

Correct the incorrect information and explain

To correct the incorrect part of the statement, we need to replace "The ionization energy for the potassium atom is negative" with "The ionization energy for the potassium atom is positive". This is because energy is required to remove an electron from an atom or ion, and thus, the ionization energy is always positive. In the case of potassium, the ionization energy is positive, and when it loses an electron, it does achieve the electron configuration of a noble gas(Argon).

Key concepts

Electron Configuration

Understanding the electron configuration of atoms is crucial in chemistry, as it dictates an atom's chemical behavior. An atom's electron configuration is the distribution of electrons in atomic or molecular orbitals.

Take the potassium (K) atom, for instance, with an atomic number of 19. It has an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1. Breaking this down, the numbers represent the energy levels, the letters indicate the types of orbitals, and the superscripts show the number of electrons in those orbitals. Potassium's configuration highlights that it has one electron in its outermost shell, the 4s orbital. This particular electron plays a significant role in potassium’s chemical reactions and is also the easiest to remove, which relates to the concept of ionization energy.

Potassium Atom

A potassium atom, denoted as K on the periodic table, carries particular significance due to its electron configuration and its tendency to lose an electron and form a K^+ ion.

This process is not without a cost of energy. The ionization energy is inherent to this journey from K to K^+. It's important to note that while the statement 'the ionization energy for the potassium atom is negative' is a misconception, the drive to achieve a stable noble gas configuration does indeed underscore the potassium atom's willingness to give up its valence electron. After losing its isolated 4s electron, the potassium ion emulates the electron configuration of argon, a noble gas, thus achieving greater stability.

Noble Gas Configuration

A noble gas configuration represents an ideal of atomic stability that many elements attempt to reach by gaining, losing, or sharing electrons. The noble gases, located in Group 18 of the periodic table, have complete outer electron shells, making them unusually nonreactive.

When potassium loses an electron, its electron configuration mirrors that of argon, a noble gas. This is due to the fact that the 'full shell' provides a more energetically favorable state, often described as the 'octet rule' for elements in the main groups of the periodic table. In aiming for this configuration, atoms like potassium become more stable, which is why they readily undergo ionization to resemble the noble gas closest to them on the periodic table.

Periodic Table Trends

The periodic table showcases trends in properties of elements that are pivotal to understanding why atoms like potassium behave the way they do. Two main trends are essential in the context of ionization energy: the energy required to remove an electron generally increases moving from left to right across a period, due to stronger attraction between the positively charged nucleus and its electrons, and decreases moving down a group as the electrons are farther from the nucleus and thus less tightly held.

Ionization Energy Trend

In potassium's case, its location on the periodic table indicates relatively low ionization energy compared to elements on its right within the same period because it has only one valence electron. This trend is consistent with our understanding of potassium’s want to achieve noble gas configuration, reinforcing these periodic table trends as an underpinning of atomic behavior in the elements.