Question

Transition metals can be defined as elements where the $d$ shell goes from empty to full. How many transition metals are there in each period? a) 2 b) 6 c) 10 d) 14

Short answer

Answer: (c) 10

Step-by-step solution

Recall the properties of transition metals

Transition metals are elements where the $d$ shell goes from empty to full. The $d$ shell can hold a maximum of 10 electrons.

Identify the location of transition metals in the periodic table

Transition metals are found between Groups 3 and 12, in periods 4 to 7, in the periodic table. They are defined by their partially filled $d$ orbitals.

Determine the number of transition metals in each period

As there are 10 groups within the range of Group 3 to Group 12, there are 10 transition metals per period. This corresponds with the $d$ shell being able to hold a maximum of 10 electrons.

Choose the correct answer

Therefore, the correct answer is (c) 10. There are 10 transition metals in each period.

Key concepts

d shell

The concept of the "d shell" is integral to understanding various chemical behaviors, particularly relating to transition metals. The "d shell" refers to a set of five atomic orbitals, which can collectively hold up to 10 electrons. This shell becomes the focus when looking at elements in the transition metal category within the periodic table. Transition metals are defined by their ability to have a partially filled d shell, either in their neutral state or when forming ions. This characteristic is one of the reasons these metals often exhibit variable oxidation states, which allows them to form colorful compounds. Additionally, the d orbitals play a pivotal role in the bonding and magnetic properties characteristic of these metals. The transition is completed when the number of electrons fills from one to ten as we move across the periodic table's periods in which they appear. These electrons in the d shell are also responsible for the complex electron configurations of these elements. Understanding the behavior and gradual population of the d shell is vital for predicting the chemical and physical properties of transition metals.

periodic table

The periodic table serves as a comprehensive map of all known elements, informing us about their structure, properties, and relationships with each other. Transition metals are situated in the center of the periodic table, specifically spanning from Groups 3 to 12. These metals are located in periods 4 through 7. While most other element groups have only one or two elements per period, the transition metals have ten. This corresponds to the gradual filling of the d shell. These metals boast unique properties such as malleability, high density, and the ability to conduct electricity and heat. They also display complex and rich chemistry due to their partially filled d orbitals. This makes them incredibly useful in various applications, including catalysis, alloy formation, and the development of magnetic materials. By studying the layout of the periodic table, we gain insights into trends such as electronegativity, atomic radius, and ionization energy, which further explain the overarching behavior of transition metals within this historical chemical tool.

electron configuration

Electron configuration is a notation that describes the distribution of electrons among the different atomic orbitals within an atom. For transition metals, this notation is particularly insightful and essential when considering their chemistry. A typical electron configuration might look something like $$\text{[Ar]}3d^{5}4s^1$$ for Iron (Fe), where electrons are distributed in different shells and subshells. For transition metals, the $d$ orbitals often come into play as electrons tend to occupy the $d$ shell before completely filling the $s$ shell of the same principal energy level. This unique characteristic leads to the metals' varied chemical properties and oxidation states. As you move across the period from left to right, electrons are progressively added to the $d$ shell, bringing about subtle changes in properties. Comprehending electron configuration is fundamental to predicting how these elements interact with others, their reactivity, formation of compounds, and the kind of bonds they form. Understanding these patterns helps us predict and rationalize the chemical behavior of transition metals as their electron configurations provide the groundwork for both their physical and chemical traits.