What is Lanthanides and Actinides: An Introduction
To explain Lanthanides and Actinides: Lanthanides and actinides are two series of elements located in the periodic table that have unique properties and play significant roles in various scientific and technological applications. Lanthanides and actinides, collectively known as inner transition elements, are two series of elements that occupy the f-block of the periodic table. Lanthanides and actinides exhibit similar electronic configurations. In the lanthanide series, the 4f sublevel progressively fills up, while in the actinide series, the 5f sublevel fills up. The lanthanides and actinides have a unique feature where the 4f and 5f orbitals are shielded from the increasing nuclear charge by the filled 5s and 5p orbitals in the lanthanide series, and the 6s and 6p orbitals in the actinide series. This leads to the relatively constant size of the atoms and the progressive filling of the inner shells. In this article, we’ll look further at the characteristics of Lanthanides and Actinides.
Defining Lanthanides
Lanthanides are a series of chemical elements that belong to the f-block of the periodic table. They are located in period 6 of the periodic table and have atomic numbers ranging from 57 (lanthanum, La) to 71 (lutetium, Lu). The lanthanide series is named after the first element in the series, lanthanum. The electronic configuration of the lanthanides is characterized by the filling of the 4f sublevel. The general outer electronic configuration for the lanthanides is $[Xe]4f^(1-14)5d^06s^2$ . This means that the 4f orbital is gradually filled as you move from lanthanum to lutetium.
Similar Chemical Behavior: Lanthanides exhibit similar chemical properties due to their comparable electronic configurations. They tend to form stable compounds and have high melting and boiling points.
Metallic Nature: Lanthanides are generally silvery-white metals that are soft and malleable.
High Density: Lanthanides are relatively dense metals, with densities higher than most other elements.
Paramagnetism: Many lanthanides show paramagnetic behavior, meaning they are weakly attracted to magnetic fields.
Colorful Compounds: Lanthanides are known for forming colorful compounds. They exhibit a wide range of colors, which makes them valuable in the production of pigments and dyes.
Catalysts: Lanthanides serve as catalysts in numerous chemical reactions, playing a crucial role in industries such as petroleum refining and pollution control.
Ceramics and Glass Manufacturing: Lanthanides contribute to the properties of ceramics and glass, enhancing their strength, thermal stability, and color.
Defining Actinides
Actinides are a series of chemical elements that belong to the f-block of the periodic table. They are located in period 7 of the periodic table and have atomic numbers ranging from 89 (actinium, Ac) to 103 (lawrencium, Lr). The electronic configuration of the actinides is characterized by the filling of the 5f sublevel. The general outer electronic configuration for the actinides is $[Rn]5f^(1-14)6d^07s^2$ . This means that the 5f orbital is progressively filled as you move from actinium to lawrencium.
Radioactivity: Most actinides are radioactive, meaning their atomic nuclei are unstable and undergo spontaneous decay, emitting radiation in the process. This is due to the presence of a large number of protons and neutrons in their atomic nuclei.
Metallic Nature: Actinides are generally silvery-white metals that are dense, malleable, and good conductors of heat and electricity.
High Atomic Mass: Actinides have relatively high atomic masses, with some of them being among the heaviest elements known.
Various Oxidation States: Actinides exhibit a wide range of oxidation states, allowing them to form a variety of compounds with different chemical properties.
Nuclear Power Generation: Actinides such as uranium and plutonium are used as fuel in nuclear reactors to produce electricity. These elements undergo fission, where their atomic nuclei split, releasing a large amount of energy.
Radiotherapy: Actinides, such as radium and americium, have been used in targeted radiation therapy for the treatment of cancer. The radioactive emissions can be directed to specifically target and destroy cancer cells.
Lanthanides and Actinides Difference
Lanthanides, and actinides are distinguished by their positions in the periodic table, electronic configurations, chemical properties, and applications. Lanthanides have the 4f sublevel filled, while actinides have the 5f sublevel filled. Actinides have diverse chemical properties, are often radioactive, and have significant roles in nuclear-related fields.
Summary
The main differences between lanthanides and actinides lie in their atomic numbers, periods in the periodic table, electronic configurations, chemical properties, and applications. Lanthanides are found in period 6 and have their 4f sublevel filled, while actinides are found in period 7 and have their 5f sublevel filled. Lanthanides have similar chemical properties, while actinides exhibit a wider range of chemical properties and are predominantly radioactive. Actinides are utilized in scientific research, particularly in nuclear physics and chemistry, as well as in the detection and measurement of radiation.
FAQs on Difference Between Lanthanides and Actinides for JEE Main 2024
1. Are lanthanides radioactive?
Lanthanides, as a group, are not inherently radioactive. Most lanthanides are stable and do not exhibit significant levels of radioactivity. However, there are a few exceptions within the lanthanide series. Promethium (Pm), which is the atomic number 61, is a radioactive element with no stable isotopes. While the majority of lanthanides are non-radioactive, it's important to note that some lanthanide isotopes can be artificially made radioactive by bombarding them with high-energy particles in a nuclear reactor or particle accelerator. These radioactive isotopes can have various uses in scientific research, medical imaging, and industrial applications. However, naturally occurring lanthanides, as found in nature, are typically non-radioactive.
2. What is the similarity between lanthanides and actinides?
Lanthanides and actinides both exhibit similar chemical behaviors within their respective series. This is primarily due to the comparable electronic configurations of the elements in each series. They tend to have high melting and boiling points, form stable compounds, and exhibit similar chemical reactivity. Lanthanides, along with the closely related element yttrium, are sometimes collectively referred to as "rare earth elements." Actinides are also included in discussions of rare earth elements due to their similar properties and associations with lanthanides in mineral deposits. other lanthanides and actinides have their outermost electrons in the f-orbitals. Lanthanides have electrons filling the 4f sublevel, while actinides have electrons filling the 5f sublevel.
3. Why are lanthanides and actinides shown separately in the periodic table?
Lanthanides and actinides are shown separately in the periodic table to maintain the overall structure and readability of the table. The periodic table is organized to show the periodic recurrence of elements based on their atomic numbers, electron configurations, and chemical properties. The separation allows for easier identification and organization of the elements while still acknowledging the presence of the lanthanides and actinides in the overall structure of the periodic table.
4. What are lanthanides also called?
Lanthanides are often referred to as "rare earth elements". The term "rare earth elements" is used to describe the lanthanide series along with the element yttrium (Y). Although the name "rare earth" might suggest their scarcity, these elements are actually relatively abundant in the Earth's crust. They are called "rare earth elements" because they were initially discovered in rare minerals and were difficult to extract.
5. What are lanthanide ores?
Lanthanide ores, also known as rare earth element ores, are natural mineral deposits that contain significant concentrations of lanthanide elements. These ores are primarily composed of a group of 17 elements, including lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and the related elements scandium (Sc) and yttrium (Y). Lanthanide ores are typically found in complex mineral deposits and can occur in association with other elements such as thorium, uranium, and phosphate.