Question

Which simple ion would each of the following elements be expected to form? What noble gas has an analogous electron configuration to each of the ions? a. chlorine, \(Z=17\) b. strontium, \(Z=38\) c. oxygen, \(Z=8\) d. rubidium, \(Z=37\)

Short answer

The simple ions and their analogous noble gases for each element are: a. Chlorine forms the chloride ion (Cl^-), analogous to Argon (Ar). b. Strontium forms the strontium ion (Sr^2+), analogous to Krypton (Kr). c. Oxygen forms the oxide ion (O^2-), analogous to Neon (Ne). d. Rubidium forms the rubidium ion (Rb^+), analogous to Krypton (Kr).

Step-by-step solution

Determine the simple ion for each element

In this step, we will look at the periodic table to determine the group number of each element and then find the simple ion they would form. a. Chlorine (Z=17) is in Group 17 of the periodic table, which means it will gain one electron to achieve a full outer electron shell. This forms the chloride ion, Cl^-. b. Strontium (Z=38) is in Group 2 of the periodic table, which means it will lose two electrons to achieve a full outer electron shell. This forms the strontium ion, Sr^2+. c. Oxygen (Z=8) is in Group 16 of the periodic table, which means it will gain two electrons to achieve a full outer electron shell. This forms the oxide ion, O^2-. d. Rubidium (Z=37) is in Group 1 of the periodic table, which means it will lose one electron to achieve a full outer electron shell. This forms the rubidium ion, Rb^+.

Find a noble gas with an analogous electron configuration for each ion

In this step, we will find a noble gas that has a similar electron configuration to the simple ion formed by each element. a. Chloride ion, Cl^-: After gaining one electron, the chloride ion has the same electron configuration as the noble gas Argon (Ar), with Z=18. b. Strontium ion, Sr^2+: After losing two electrons, the strontium ion has the same electron configuration as the noble gas Krypton (Kr), with Z=36. c. Oxide ion, O^2-: After gaining two electrons, the oxide ion has the same electron configuration as the noble gas Neon (Ne), with Z=10. d. Rubidium ion, Rb^+: After losing one electron, the rubidium ion has the same electron configuration as the noble gas Krypton (Kr), with Z=36. The simple ions and their analogous noble gases for each element are: a. Chlorine - Chloride ion (Cl^-) - Argon (Ar) b. Strontium - Strontium ion (Sr^2+) - Krypton (Kr) c. Oxygen - Oxide ion (O^2-) - Neon (Ne) d. Rubidium - Rubidium ion (Rb^+) - Krypton (Kr)

Key concepts

Ion Formation

When elements form ions, they are doing so to achieve a stable electron configuration. This configuration often mirrors that of a noble gas, a group of elements known for their stability due to having a complete set of electrons in their outer shell.
To ascertain the formation of ions, you first need to understand the behavior of elements in terms of their valence electrons, which are the electrons in the outermost shell.

• Metals typically lose electrons to form positively charged ions, known as cations.
• Non-metals, conversely, gain electrons to form negatively charged ions, known as anions.

For example, chlorine (Cl), found in Group 17 in the periodic table, gains one electron to complete its outer shell and forms the chloride anion (Cl^-). Meanwhile, strontium (Sr), from Group 2, loses two electrons to form the strontium cation (Sr^{2+}). This electron loss or gain helps the element attain a balance similar to that of the nearest noble gas.

Noble Gases

Noble gases are a unique and stable group within the periodic table. They can be found in Group 18 and have highly desirable electron configurations because their outermost shell is full.
Their stability is what other elements aim to replicate during ion formation.

• Since the noble gases have complete valence electron shells, they rarely react with other elements.
• The inert nature of noble gases is due to this full electronic configuration, making empty openings rare.

For instance, when chlorine becomes an ion by gaining an electron to form Cl^-, it mirrors argon's electron configuration. Similarly, oxygen gains electrons to resemble the structure of neon. Elements find stability mimicking these configurations, reducing their reactivity.

Periodic Table

The periodic table is an essential tool in the study of chemistry, organizing all known elements by increasing atomic number and by recurring chemical properties.
Understanding the periodic table helps predict how an element might interact with others and whether it might form an ion.

• Elements are grouped in vertical columns known as groups, characterized by having the same number of valence electrons.
• Horizontally, elements are placed in periods, indicating the number of electron shells an element's atoms will have.

For example, rubidium in Group 1 has a single available electron which it can easily lose to form Rb^+, aligning its configuration with that of krypton. Understanding the groups and periods allows prediction of ionization patterns among elements.

Chemical Elements

Chemical elements are substances that consist of one type of atom, each defined by its atomic number, which represents the number of protons in its nucleus.
Elements can exist as singular atoms or bond with identical or different atoms to form compounds.

• Each element behaves distinctively with its own properties, primarily derived from its electron configuration.
• Elements seek stability by completing their outer shells, often through forming ions to match the electron count of a nearby noble gas.

For example, the chemical element oxygen tends to gain electrons, filling its valence shell to become more stable. Elements like strontium, on the other hand, tend to lose a few electrons to reach the stable electron configuration seen in krypton. This pursuit of stability underscores why elements form the ions they do.