Question

Which of the following does not form ionic compound easily? (a) Thalium (b) Aluminium (c) Boron (d) Galium

Short answer

Boron does not form ionic compounds easily.

Step-by-step solution

Understanding Ionic Compounds

Ionic compounds are formed through the transfer of electrons between atoms. This usually involves a metal donating electrons to a non-metal, creating positive and negative ions that attract each other.

Review the Elements Given

Consider the options given: Thallium, Aluminium, Boron, and Gallium. Thallium, Aluminium, and Gallium are metals, while Boron is a metalloid.

Examine Electron Configurations

Metals tend to lose electrons easily to form positive ions, while non-metals tend to gain them. Boron, being a metalloid, does not easily lose electrons to form an ionic bond.

Identify the Least Likely to Form Ionic Bonds

Since Boron is a metalloid and does not easily lose electrons to form positive ions like metals do, it is the least likely to form ionic compounds compared to the other options.

Key concepts

Metalloid Properties

Metalloids, often referred to as semimetals, have properties that are intermediate between metals and non-metals. These unique properties make metalloids versatile in various applications, from electronics to materials science. Here are some characteristics of metalloids:

• Semiconductive Behavior: Metalloids can conduct electricity better than non-metals but not as well as metals. This property makes them useful in electronics, such as in computer chips and transistors.
• Physical Properties: Metalloids often have a mixed appearance, being shiny like metals while being brittle like non-metals.
• Chemical Reactivity: Metalloids tend to form covalent bonds rather than ionic bonds, due to their intermediate electronegativity.

This combination of properties means that metalloids, like boron, behave differently from metals and non-metals, affecting how they form compounds.

Electron Transfer

The transfer of electrons is a fundamental process behind the formation of ionic compounds. Here’s a simple breakdown of how electron transfer works:

• Metal Atoms: These typically have few electrons in their outer shell and tend to lose them, forming positively charged ions or cations.
• Non-Metal Atoms: These have more electrons in their outer shell and tend to gain extra electrons to achieve a full outer shell, forming negatively charged ions or anions.
• Attraction of Ions: The oppositely charged ions attract each other strongly, resulting in an ionic compound with a stable structure.

However, metalloids like boron do not easily partake in this electron transfer due to their semi-metallic nature, which makes them less likely to form ionic compounds compared to metals.

Boron Chemistry

Boron, a member of the metalloids, exhibits unique chemical characteristics that influence its behavior in compound formation. Unlike its metal companions, boron does not easily form ionic bonds. Here’s why:

• Electron Configuration: Boron has three electrons in its outer shell, which makes it unlikely to either completely lose or gain electrons like metals or non-metals.
• Covalent Bond Formation: Boron often forms covalent, rather than ionic bonds, sharing electrons instead of transferring them. An example is boron trifluoride (BF3), where boron shares electrons with fluorine atoms.
• High Ionization Energy: The energy required to remove electrons from boron is relatively high, which discourages the formation of positive ions necessary for ionic bonding.

These properties mean that in comparisons of elements' ability to form ionic compounds, boron stands out as less likely due to its tendency to form covalent structures.

Metallic Behavior

Metals are known for their unique behaviors, especially when it comes to losing electrons and forming ionic bonds. Here are some typical traits of metallic behavior that apply to elements like thallium, aluminium, and gallium:

• Electron Donation: Metals tend to lose their outer electrons readily, forming cations. This loss contributes to forming ionic bonds with non-metal atoms.
• Electrical Conductivity: Metals are excellent conductors of electricity because of their free-moving electrons, which also attract and bond with non-metals to form ionic compounds.
• Malleability and Ductility: Metals can be easily shaped or stretched into wires, a physical property due to their structure of positively charged ions within a "sea" of mobile electrons.

Because of these characteristics, metals naturally form ionic compounds, unlike boron, which behaves distinctively due to its metalloid nature.