Question

For each pair of elements listed, predict which one has more stable isotopes: (a) Co or \(\mathrm{Ni},\) (b) \(\mathrm{F}\) or \(\mathrm{Se}\) (c) Ag or Cd.

Short answer

(a) Nickel (Ni), (b) Selenium (Se), and (c) Cadmium (Cd) each have more stable isotopes.

Step-by-step solution

Analyze Co and Ni

Consult the periodic table or isotopic reference resource to determine the number of stable isotopes each of these elements has. The number of stable isotopes for Co (Cobalt) is 1, and Ni (Nickel) has 5.

Analyze F and Se

Perform the same analysis for F (Fluorine) and Se (Selenium). Fluorine has 1 stable isotope, whereas Selenium contains 5 stable isotopes.

Analyze Ag and Cd

Finally, review the isotopic data for Ag (Silver) and Cd (Cadmium). Silver has 2 stable isotopes and Cadmium has 8 stable isotopes.

Key concepts

Isotopic Reference

Isotopic references are essential for understanding the stable isotopes of elements. These references provide a catalog of isotopes associated with each element. This information helps scientists and students predict physical and chemical behaviors. An isotope is a variant of an element with the same number of protons but different numbers of neutrons. The stability of these isotopes is determined by their ability to resist radioactive decay over long periods. In chemistry and physics, knowing which isotopes are stable allows for accurate experimentation and data collection. Accessing an isotopic reference can clarify these traits for any given element.

Periodic Table

The periodic table organizes elements according to their atomic number and properties, acting as a roadmap for chemists. Each element has a unique position on the table, denoting its atomic structure, including isotopes. This systematic arrangement helps in identifying trends, such as isotopic distribution. The periodic table also reveals patterns in elemental groups, aiding predictions about isotopes. For instance, elements in the same group often exhibit similar isotopic characteristics. By consulting the table, students can quickly discern potential isotopic stability, helping them solve exercises involving isotopic comparison.

Element Comparison

Element comparison is crucial when analyzing isotopic stability. Comparing elements involves looking at various factors such as atomic number, mass number, and isotopic abundance. This process helps determine which element possesses more stable isotopes. In the given exercise, for example, students compare pairs of elements to predict which has more stable isotopes. Such comparisons require knowledge of how isotopes vary among elements and how this affects their stability. The process of element comparison is a practical exercise in applying periodic table information to real-world isotope data.

Cobalt

Cobalt, with the chemical symbol Co, is a sturdy transition metal known for its magnetic properties. Interestingly, cobalt has only one stable isotope,

• Mass number: 59

This single stable isotope makes cobalt unique compared to other transition metals which often have multiple stable isotopes. Despite having just one stable isotope, cobalt is highly valuable in industrial applications. It is prominently used in high-strength alloys and batteries. In the context of isotopic comparison, cobalt serves as a benchmark when evaluating other elements with varying isotopic numbers.

Nickel

Nickel (Ni) is another vital transition metal, noted for its utility in corrosion-resistant alloys. Unlike cobalt, nickel boasts five stable isotopes,

• Mass numbers: 58, 60, 61, 62, and 64

These multiple stable isotopes contribute to nickel's adaptability and usage in various chemical reactions and industrial applications. The abundance of stable isotopes makes nickel a perfect candidate for isotopic studies, providing rich data on elemental behavior. Its multiple stable isotopes also allow researchers to explore nickel's role in geological processes.

Fluorine

Fluorine (F) is a highly reactive halogen, recognized for its extreme reactivity. It has a single stable isotope,

• Mass number: 19

Fluorine's isotopic simplicity contrasts with its chemical complexity, as it forms compounds with almost all elements. This single isotope provides clarity and a straightforward approach for scientists studying fluorine's properties. In isotopic comparisons, fluorine's one stable isotope makes it less variable compared to elements like selenium.

Selenium

Selenium (Se) is an essential non-metal known for its photoconductivity and use in electronics. It possesses five stable isotopes,

• Mass numbers: 74, 76, 77, 78, and 80

Selenium's multiple stable isotopes support its crucial functions in biology, particularly in enzyme activities. These isotopes provide selenium a versatile role in scientific research, often used to track biochemical processes. In comparison with fluorine, selenium's isotopic diversity offers richer opportunities for analytical studies and applications.

Silver

Silver (Ag) is a precious metal famed for its conductivity and reflectivity. It has two stable isotopes,

• Mass numbers: 107 and 109

These isotopes make silver resilient and malleable, ideal for electrical applications and jewelry. Silver's relative abundance of stable isotopes provides leverage in comparisons, demonstrating moderate isotopic diversity. This makes silver favorable in isotopic analysis, where tracking natural abundance and elemental transformations is required.

Cadmium

Cadmium (Cd) is another transition metal, known for its use in batteries and pigments. Cadmium has the remarkable characteristic of eight stable isotopes,

• Mass numbers: 106, 108, 110, 111, 112, 113, 114, and 116

The abundance of stable isotopes in cadmium allows for extensive scope in isotope study and environmental applications. These isotopes make cadmium highly significant for exploring radioactive decay phenomena. In isotopic comparison exercises, cadmium demonstrates a wide isotopic range, illustrating its adaptability and the broad impact of isotopic diversity.