Question

\(\mathrm{B}\) The "Chemistry in Focus" segment A Magnetic Moment discusses the ability to levitate a frog in a magnetic field because electrons, when sensing a strong magnetic field, respond by opposing it. This is called diamagnetism. Atoms that are diamagnetic have all paired electrons. Which columns among the representative elements in the periodic table consist of diamagnetic atoms? Consider orbital diagrams when answering this question.

Short answer

Among the representative elements in the periodic table, columns that consist of diamagnetic atoms include Group 2 (alkaline earth metals) and Group 18 (noble gases), as they have fully filled s and p orbitals in their respective electron configurations.

Step-by-step solution

Recall the Electron Configuration and Orbital Diagrams

Recall that electrons fill subshells in a specific order (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, ...). The elements in the periodic table can be represented by their electron configurations, showing how many electrons occupy each subshell. In an orbital diagram, electrons are represented by arrows shown within boxes, which represent their respective orbitals.

Examine the representative elements

We will focus on the representative elements, which are found in groups 1, 2, 13-18 (columns) of the periodic table.

Determine the electron configurations and identify paired electrons

Group 1 (alkali metals) - Their electron configuration is [Noble gas] ns1. Since there is only 1 unpaired electron, these elements are not diamagnetic. Group 2 (alkaline earth metals) - Their electron configuration is [Noble gas] ns2. Since their s orbitals are fully filled, these elements are diamagnetic. Group 13 - Their electron configuration is [Noble gas] ns2 np1. Since their p orbitals are not fully filled, these elements are not diamagnetic. Group 14 - Their electron configuration is [Noble gas] ns2 np2. Since their p orbitals are not fully filled, these elements are not diamagnetic. Group 15 - Their electron configuration is [Noble gas] ns2 np3. Since their p orbitals are not fully filled, these elements are not diamagnetic. Group 16 - Their electron configuration is [Noble gas] ns2 np4. Since their p orbitals are not fully filled, these elements are not diamagnetic. Group 17 (halogens) - Their electron configuration is [Noble gas] ns2 np5. Since their p orbitals are not fully filled, these elements are not diamagnetic. Group 18 (noble gases) - Their electron configuration is [Noble gas] ns2 np6, with the exception of helium, which has configuration 1s2. Since their s and p orbitals are fully filled, these elements are diamagnetic.

List the columns with diamagnetic atoms

From the analysis above, we can conclude that columns that consist of diamagnetic atoms among the representative elements are: 1. Group 2 (alkaline earth metals) 2. Group 18 (noble gases)

Key concepts

Electron Configuration

Electron configuration is a method of indicating the distribution of electrons in an atom's orbitals. This pattern helps us understand how electrons occupy different energy levels and subshells. When constructing electron configurations, we start from the lowest energy level and fill orbitals according to the Aufbau principle. This order generally follows the sequence: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, and so on. For example:

• Sodium (Na), with atomic number 11, has the electron configuration: 1s² 2s² 2p⁶ 3s¹.
• Neon (Ne), with atomic number 10, has the electron configuration: 1s² 2s² 2p⁶.

These configurations are crucial in understanding the chemical behavior of elements. By analyzing the arrangement of electrons, scientists can predict how an atom will interact with others, determining whether it will gain, lose, or share electrons during chemical reactions.

Periodic Table Groups

The periodic table is organized in a manner that groups elements with similar properties. These groups, or columns, are numbered and consist of elements that exhibit similar chemical behaviors due to their electron configurations. Key groups include:

• Group 1: Known as alkali metals, they have a configuration ending in ns¹ and are very reactive due to their single unpaired electron.
• Group 2: The alkaline earth metals have their outermost s orbital filled (ns²), making them generally reactive, but less so than Group 1 metals. They are diamagnetic due to all paired electrons.
• Groups 13 to 18: These include metals, metalloids, and non-metals. Groups 15 to 17 have partially filled p orbitals, leading them to exhibit a range of chemical behaviors.
• Group 18: Known as noble gases, these elements have fully filled s and p orbitals (ns² np⁶) resulting in a stable configuration and diamagnetic properties.

Understanding these groups helps us predict the properties and behaviors of various elements, making the periodic table an indispensable tool in chemistry.

Representative Elements

Representative elements, often referred to as "main group elements," belong to groups 1, 2, and 13-18 in the periodic table. These elements span the entire range of nonmetals, metalloids, and metals, showcasing diverse chemical properties.

• In Group 1 (alkali metals) and Group 2 (alkaline earth metals), electron configurations end in the s orbital. Group 1 is characterized by a single electron in the outer s shell, making them highly reactive. Group 2 completes the s orbital, making them more stable and diamagnetic.
• Elements in Groups 13-18 are known for having their highest-energy electrons in p orbitals. For example, Group 18's noble gases have fully filled p orbitals, leading to exceptional stability and lack of reactivity.

Representative elements typically form predictable compounds and follow standard periodic trends, such as increasing electronegativity across periods and decreasing reactivity across groups.

Paired Electrons

Paired electrons are those that are found together in an orbital, occupying the same space but with opposite spins, in accordance with the Pauli Exclusion Principle. This pairing is significant because it affects an atom’s magnetic properties.

• When all electrons in an atom are paired, the atom is diamagnetic. Diamagnetic substances are repelled by magnetic fields due to the cancellation of the magnetic moments of paired electrons.
• Unpaired electrons, on the other hand, confer paramagnetism, where atoms are attracted to magnetic fields due to the presence of unbalanced magnetic moments.

In the context of the periodic table, elements such as the alkaline earth metals (Group 2) and noble gases (Group 18) exhibit diamagnetism because their electron configurations result in all electrons being paired. This feature differentiates them from other groups that have unpaired electrons, affecting their magnetic and chemical behaviors.