Question

Among the period 4 transition metals \((\mathrm{Sc}-\mathrm{Zn}),\) which elements do not form ions where there are partially filled 3d orbitals?

Short answer

Sc and Zn are the elements among the period 4 transition metals that do not form ions with partially filled 3d orbitals. This is because Sc forms Sc3+ ions with an electron configuration of [Ar] 3d0, and Zn forms Zn2+ ions with an electron configuration of [Ar] 3d10.

Step-by-step solution

List the Period 4 Transition Metals

The period 4 transition metals are: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn.

Write Electron Configurations

The electron configurations (in the neutral state) for these elements are: \(1.\) Sc: [Ar] 3d1 4s2 \(2.\) Ti: [Ar] 3d2 4s2 \(3.\) V: [Ar] 3d3 4s2 \(4.\) Cr: [Ar] 3d5 4s1 \(5.\) Mn: [Ar] 3d5 4s2 \(6.\) Fe: [Ar] 3d6 4s2 \(7.\) Co: [Ar] 3d7 4s2 \(8.\) Ni: [Ar] 3d8 4s2 \(9.\) Cu: [Ar] 3d10 4s1 \(10.\) Zn: [Ar] 3d10 4s2

Determine Ionized Forms

Upon ionization, electrons will be lost first from the 4s orbital, followed by the 3d orbital. Let's consider the common ionized forms of these elements: \(1.\) Sc: [Ar] 3d0 (Sc3+) - No partially filled 3d orbitals. \(2.\) Ti: [Ar] 3d1 (Ti3+) - Partially filled 3d orbitals. \(3.\) V: [Ar] 3d2 (V3+) - Partially filled 3d orbitals. \(4.\) Cr: [Ar] 3d3 (Cr3+) - Partially filled 3d orbitals. \(5.\) Mn: [Ar] 3d4 (Mn3+) - Partially filled 3d orbitals. \(6.\) Fe: [Ar] 3d5 (Fe3+) - Partially filled 3d orbitals. \(7.\) Co: [Ar] 3d6 (Co3+) - Partially filled 3d orbitals. \(8.\) Ni: [Ar] 3d7 (Ni3+) - Partially filled 3d orbitals. \(9.\) Cu: [Ar] 3d9 (Cu1+) - Partially filled 3d orbitals. \(10.\) Zn: [Ar] 3d10 (Zn2+) - No partially filled 3d orbitals.

Identify Elements without Partially Filled 3d Orbitals

From the ionized forms, we can identify that Sc and Zn do not have partially filled 3d orbitals when forming ions.

Key concepts

Electron Configurations

Understanding the electron configurations of atoms is fundamental in predicting chemical properties and behaviors. The electron configuration describes the distribution of electrons among the available orbitals in an atom. Electrons occupy orbitals starting from the lowest energy level and move up to higher levels as necessary.

For transition metals, which include elements in groups 3 to 12 of the periodic table, their electron configurations can be more complex due to the filling of the d-orbitals. When writing electron configurations for these metals, we consider both the 3d and 4s orbitals. Typically, the 4s orbital is filled before the 3d orbitals because it is higher in energy. This can seem counterintuitive since the 4s orbital is written after the 3d when representing electron configurations.

When transition metals ionize to form cations, they often lose their 4s electrons first, despite these being the last electrons they gained. Recognizing this pattern is key to predicting the electron configurations of ionized transition metals.

d-Orbitals

The d-orbitals are a set of five orbitals found in the third shell and beyond. They are designated as dxy, dyz, dzx, dx^2-y^2, and dz^2. These orbitals have distinctive shapes and are oriented differently in space, which allows for a more complex arrangement of electrons.

In transition metals, the d-orbitals play a significant role because they accommodate up to ten electrons, which is critical for their unique properties, such as variable oxidation states and coloration. The d-orbitals are not completely filled in the neutral atom of most transition metals. However, when they form ions, the question arises as to whether these d-orbitals become fully filled, remain partially filled, or are emptied completely.

This characteristic greatly influences the chemical behavior of transition metals. For instance, the metallic bonding, magnetic properties, and catalytic activities of these elements are intimately related to the occupancy of their d-orbitals.

Periodic Table

The periodic table is arranged in such a way that elements with similar electron configurations and properties are aligned in columns known as groups or families. Within the periodic table, the transition metals are positioned in the center, specifically from groups 3 to 12.

These metals are typically characterized by their ability to form variable oxidation states, primarily due to their d-orbitals. The period in which a transition metal lies dictates how many principal energy levels (shells) the element has. For the period 4 transition metals, for instance, the 3d and 4s subshells are being filled. Understanding the structure of the periodic table helps to predict ionization patterns and the resulting electron configurations after ion formation.

Ion Formation

Ionization is the process by which an atom gains or loses electrons to form ions. Transition metals usually lose electrons to form positive ions or cations. The ease of ion formation and the charges of the resulting ions are influenced by factors such as the atomic size, ionization energy, and electron configuration of the metal.

During ionization, transition metals first lose electrons from the s orbital, which is of higher energy, and then from the d orbitals if further ionization occurs. The resulting electron configuration may or may not include partially filled d orbitals. This aspect is critical for determining the magnetic properties and other behaviors of the ions produced. For example, Scandium (Sc) loses all three of its valence electrons to form a Sc3+ ion with an electron configuration of [Ar] 3d0, which means there are no partially filled 3d orbitals remaining.