Question

The elements with atomic numbers of 93 or greater are referred to as the ______________ elements.

Short answer

The elements with atomic numbers of 93 or greater are referred to as the Transuranium elements.

Step-by-step solution

Understanding atomic numbers

Atomic number is the number of protons in the nucleus of an atom, which determines its position in the periodic table. The elements in the periodic table are arranged in order of increasing atomic numbers. As the atomic number increases, the properties of elements change.

Analyzing periodic table

In the periodic table, there are several groups and periods of elements. By looking at the elements with atomic numbers 93 or greater, we can see that these elements are located in the Actinide series.

Identifying the term

The elements with atomic numbers of 93 or greater are referred to as the Transuranium elements. The reason these elements are called Transuranium elements is that their atomic numbers are greater than Uranium (which has atomic number 92). This means they are elements that have more protons in their nucleus than Uranium. Most of these elements are artificially synthesized and not found in nature, as they are generally unstable and radioactive.

Key concepts

Atomic Number

The atomic number is a fundamental concept in chemistry and is integral for understanding the composition and properties of elements on the periodic table. It is represented by the symbol 'Z' and strictly refers to the number of protons found in the nucleus of an atom. The atomic number is unique to each element, meaning no two elements share the same atomic number, making it an essential identifier for elements.

The significance of atomic numbers extends beyond mere counting. It determines the chemical behavior of an element since the number of protons influences the electronic structure surrounding the nucleus. With a greater number of protons, the positive charge in the nucleus increases, attracting more electrons and altering the way an element interacts with others.

• Hydrogen, with a single proton, has an atomic number of 1.
• Oxygen, with eight protons, has an atomic number of 8.
• Uranium, with 92 protons, has an atomic number of 92.

Understanding atomic numbers is crucial when exploring elements on the periodic table, especially when investigating the transuranium elements which have atomic numbers greater than Uranium.

Periodic Table

The periodic table is a tabular arrangement of the chemical elements, organized by their atomic numbers, electron configurations, and recurring chemical properties. Elements are presented in order of increasing atomic number in rows called periods and columns known as groups or families.

The layout of the periodic table is designed to showcase patterns and relationships among the elements. For instance, elements with similar chemical properties fall into the same group, such as the noble gases in group 18 that are all colorless, odorless, and almost completely non-reactive. The table is also divided into four blocks – s, p, d, and f – based on the electron subshell filled with the last electron.

• The 's' block includes the first two groups along with helium.
• The 'p' block consists of groups 13 to 18.
• The 'd' block comprises the transition metals in the center of the table.
• The 'f' block, at the bottom, contains the lanthanides and actinides.

Mastery of the periodic table's organization aids in predicting the properties and behaviors of various elements, especially when it comes to the study of transuranium elements found in the actinide series.

Actinide Series

The Actinide series, a group of elements on the periodic table, is located at the bottom row of the 'f' block and includes elements with atomic numbers from 89 (Actinium) to 103 (Lawrencium). This series is a subset of the transuranium elements, which are all the elements beyond uranium (atomic number 92) on the periodic table.

Actinide elements share common features: they are all radioactive, and most are not naturally occurring. These elements are typically synthesized in nuclear reactors or particle accelerators. The Actinides are known for their complex electron configurations, which influence their chemical and physical properties, leading to significant scientific and practical interest, particularly in the fields of nuclear energy and medicine.

• Neptunium (93) and Plutonium (94) are the first transuranium elements in the series.
• Americanium (95) is commonly used in smoke detectors.
• Californium (98) has applications in starting nuclear reactors and treating cancer.

The study of Actinides is complex due to their radioactive nature and requires specialized knowledge and safety precautions. Nonetheless, their unique characteristics make them intriguing for scientific research and potential applications.