Question

For each pair of elements listed, predict which one has more stable isotopes: (a) I or Sn (b) Ga or \(\mathrm{Ni}\) (c) Si or Cl

Short answer

(a) I (Iodine) and Sn (Tin), (b) Ga (Gallium) and Ni (Nickel), (c) Si (Silicon) and Cl (Chlorine). Answer: (a) Sn (Tin) has more stable isotopes than I (Iodine). (b) Ni (Nickel) has more stable isotopes than Ga (Gallium). (c) Si (Silicon) has more stable isotopes than Cl (Chlorine).

Step-by-step solution

(a) Comparing stable isotopes of I (Iodine) and Sn (Tin)

To compare the stable isotopes of Iodine (I) and Tin (Sn), we will look up the number of stable isotopes for each element from a reliable source. After some research, we find that Iodine has 1 stable isotope, while Tin has 10 stable isotopes. Therefore, Sn (Tin) has more stable isotopes than I (Iodine).

(b) Comparing stable isotopes of Ga (Gallium) and Ni (Nickel)

Similarly, we will compare the stable isotopes of Gallium (Ga) and Nickel (Ni) by researching the number of stable isotopes for each element. We find that Gallium has 2 stable isotopes, while Nickel has 5 stable isotopes. Therefore, Ni (Nickel) has more stable isotopes than Ga (Gallium).

(c) Comparing stable isotopes of Si (Silicon) and Cl (Chlorine)

Finally, we will compare the stable isotopes of Silicon (Si) and Chlorine (Cl) by looking up their respective numbers of stable isotopes. We find that Silicon has 3 stable isotopes, while Chlorine has 2 stable isotopes. Therefore, Si (Silicon) has more stable isotopes than Cl (Chlorine).

Key concepts

Isotopic Stability

Isotopic stability refers to the tendency of an isotope of a chemical element to remain unchanged or undecayed over time. A stable isotope does not undergo radioactive decay and remains constant in nature. The stability of isotopes is influenced by the ratio of neutrons to protons in an atom's nucleus. Atoms with too few or too many neutrons compared to protons will often be unstable and radioactive. However, the 'magic numbers' of nucleons (both neutrons and protons), such as 2, 8, 20, 50, 82, or 126, contribute to greater stability.

Isotopic stability is a crucial concept in understanding elements and their interactions. It plays a significant role in fields ranging from chemistry and physics to environmental science and geology, where stable isotopes are used as tracers or for dating. For example, the carbon-12 isotope is stable and prevalent, making it the standard against which atomic masses are measured.

Elements tend to have a higher number of stable isotopes when they have a balanced neutron-to-proton ratio and fall within the aforementioned magic numbers. Tin (Sn), for instance, with 10 stable isotopes, has a relatively high number of magic numbers among its isotopes, enhancing its overall isotopic stability.

Chemical Elements

Chemical elements are the basic building blocks of matter and consist of atoms that have the same number of protons in their nucleus. The periodic table organizes these elements based on their atomic number (the number of protons) and chemical properties. Each element can have numerous isotopes, which are atoms with the same number of protons but different numbers of neutrons. The presence of different isotopes means that an element can exhibit variations in mass and stability.

The atomic structure of a chemical element defines its stability, reactivity, and place in the periodic table. Elements like Iodine (I), with a single stable isotope, or Chlorine (Cl), with two, show how diverse elements can be in terms of their isotopic profiles. Understanding the number and types of stable isotopes an element has provides insight into the element's nuclear structure and its behavior in natural and experimental settings. Moreover, this knowledge is essential for applications such as medical diagnostics, where isotopes are used in imaging and treatment.

Predicting Isotope Stability

Predicting isotope stability involves understanding the principles that contribute to nuclear stability. A key principle is the neutron-to-proton (n/p) ratio. Isotopes with an ideal n/p ratio are more likely to be stable. Additionally, the concept of 'nuclear shells' similar to electron shells in chemistry, proposes that certain numbers of nucleons form complete shells within the nucleus, providing enhanced stability. Compounds near or at these 'magic numbers' of protons or neutrons are usually more stable.

For educational purposes, one can usually predict the relative stability of isotopes by consulting the periodic table and nuclear shell model. By counting the number of protons and neutrons and comparing them to the known magic numbers, you can often make an educated guess about an isotope's stability. However, there are exceptions and variations, mainly due to the complexity of atomic forces and quantum effects, which can only be fully understood through advanced study and experimentation.

For instance, in a classroom setting, when asked which element between Gallium (Ga) and Nickel (Ni) has more stable isotopes, one would look at the proton count and known stable isotopes to inform their prediction. Since Nickel has more stable isotopes than Gallium, it suggests that Nickel's nuclear properties confer upon it a higher degree of stability. This prediction process underscores the balance and arrangement of subatomic particles in rendering an isotope stable or unstable.