Question

From their positions on the periodic table, will Cu and I form a molecular compound or an ionic compound?

Short answer

Cu and I will form an ionic compound.

Step-by-step solution

Identify Element Types

First, identify what types of elements copper (Cu) and iodine (I) are. Copper (Cu) is a metal, while iodine (I) is a non-metal.

Understand Compound Types

Next, recall the difference between ionic and molecular (covalent) compounds. Ionic compounds typically form between metals and non-metals, where electrons are transferred to create ions. Molecular compounds usually form between non-metals, where electrons are shared.

Predict Compound Type

Given that Cu is a metal and I is a non-metal, these elements are likely to form an ionic compound. Metals like Cu tend to lose electrons and become cations, while non-metals like I gain electrons and become anions.

Key concepts

Periodic Table

The periodic table is an essential tool in chemistry. It systematically organizes all known chemical elements according to their atomic number, electron configuration, and recurring chemical properties.
By looking at the table, elements can be classified into metals, non-metals, and metalloids based on their properties and position.
Metals are usually found on the left side and middle of the table, while non-metals are located on the right side.
Understanding an element's position helps predict its chemical behavior, such as whether it will form ionic or covalent bonds.

• Elements are arranged in rows called periods and columns known as groups or families.
• Group numbers can hint at valence electron count—important for predicting bond types and reactivity.
• Transition metals, like copper (Cu), are found in the center and have variable oxidation states.

The periodic table is thus a roadmap for understanding how different elements interact and bond together.

Metal and Non-metal Elements

Identifying whether an element is a metal or a non-metal is crucial for predicting the type of compounds they will form.
Metals, like copper (Cu), have certain distinctive features such as:

• Shiny appearance
• Conductivity (heat and electricity)
• Malleability and ductility
• Tendency to lose electrons and form positive ions (cations)

On the other hand, non-metals, like iodine (I), exhibit different properties:

• Dull appearance (in solid form)
• Poor conductivity
• Often brittle when solid
• Tendency to gain electrons and form negative ions (anions)

While metals and non-metals have distinct characteristics, their interactions are fascinating.
For example, when metals and non-metals come together, they usually form ionic compounds because of their electron transfer tendencies.

Electron Transfer

Electron transfer is the foundational concept behind ionic bonding. When metals and non-metals interact, the process involves the movement of electrons from one atom to another, leading to the creation of ions.
Metals, which have fewer valence electrons, tend to lose these electrons, resulting in a positively charged ion or cation. For example, copper (Cu) often loses electrons to form ions like Cu²⁺.
Conversely, non-metals, which have more nearly complete valence shells, gain electrons to attain a full outer electron shell, creating negatively charged ions or anions. Iodine (I), for instance, can gain an electron to become I⁻.

• Electron transfer enables metals and non-metals to achieve stable electron configurations similar to noble gases.
• The created cations and anions are attracted to each other due to opposite charges, forming ionic compounds.
• Such ionic bonds lead to the formation of crystalline solids, which have high melting and boiling points.

This process of electron transfer is what forms the basis of ionic bonding and helps in the prediction and formation of ionic compounds.