Question

Using electron-dot structures, diagram the formation of an ionic bond between potassium and iodine

Short answer

Potassium (K) has 1 valence electron, and iodine (I) has 7 valence electrons. Their electron-dot structures are represented as: \(K\cdot \) and \(\cdot I \: \cdot \: \cdot \: \cdot \: \cdot \). Potassium transfers its 1 valence electron to Iodine, forming a positively charged ion (K^+) and negatively charged ion (I^-). The ionic bond between K and I is formed due to electrostatic attraction, resulting in the ionic compound \(K^+ I^-\).

Step-by-step solution

Identify the number of valence electrons for each atom

To determine the electron-dot structures for potassium (K) and iodine (I), we need to know the number of valence electrons. Potassium is in group 1 of the periodic table and has 1 valence electron. Iodine is in group 17 and has 7 valence electrons.

Represent the atoms with their electron-dot structures

We can now form the electron-dot structures for potassium and iodine. An electron-dot structure shows the symbol of the element and one dot for each valence electron. Potassium is represented as: \[K\cdot \] Iodine is represented as: \[\cdot I \: \cdot \: \cdot \: \cdot \: \cdot \]

Formation of the ionic bond

In an ionic bond, one or more electrons are transferred from one atom to another, resulting in the formation of positive and negative ions. These ions are attracted to each other due to their opposite charges. Since potassium has only one valence electron, it will lose that electron to achieve a stable electron configuration. Iodine, on the other hand, needs one more electron to have a full valence shell, so it will gain the electron that potassium loses. The electron transfer can be represented as follows: \[K\cdot \rightarrow K^+ + e^-\] \[\cdot I \: \cdot \: \cdot \: \cdot \: \cdot \: + e^- \rightarrow \: \cdot I^- \: \cdot \: \cdot \: \cdot \: \cdot \]

Formation of the ionic compound

After the electron transfer, potassium becomes a positively charged ion (K^+) and iodine becomes a negatively charged ion (I^-). The electrostatic attraction between these oppositely charged ions results in the formation of an ionic bond. The final ionic compound can be represented as: \[K^+ \: I^-\] Thus, the formation of an ionic bond between potassium and iodine has been diagrammed using electron-dot structures.

Key concepts

Electron-Dot Structures

Electron-dot structures, also known as Lewis dot structures, provide a visual way to represent the valence electrons of atoms. These structures are incredibly straightforward: the chemical symbol of the element is used to represent the atom itself, while dots placed around the symbol indicate the number of valence electrons.

When drawing electron-dot structures for, say, potassium (K) with one valence electron, you simply place a single dot beside the 'K' symbol. Iodine (I), with seven valence electrons, will have seven dots arranged in pairs to represent each electron. These pairs reflect the tendency of electrons to pair up whenever possible, which is a crucial element of chemical bonding.

Utilizing these simple representations allows us to visualize how atoms share or transfer electrons to form chemical bonds, which is fundamental when studying the behavior of elements and the compounds they form. Let's connect this to the electron-dot structures used between potassium and iodine, depicting an electron transfer, which is key to understanding the formation of ionic bonds.

Valence Electrons

Valence electrons are the electrons that are located in an atom's outermost shell and they play a critical role in chemical bonding. They determine how an atom will interact with others to form compounds. The number of valence electrons can be easily determined from an element's group number on the periodic table, with some exceptions. For example, all elements in group 1 have one valence electron, which is the case for potassium in our exercise.

These electrons can be gained, lost, or shared during the formation of chemical bonds, leading to the creation of molecules and ionic compounds. Groups 1 and 17 elements, such as potassium and iodine respectively, are particularly important for ionic bonding. Potassium readily gives up its lone valence electron while iodine is eager to accept an additional electron to complete its octet, demonstrating the push and pull of chemical reactivity that underpins the formation of ionic bonds.

Chemical Bonding

Chemical bonding is the process by which atoms combine to form compounds. There are several types of chemical bonds, but one of the most common is the ionic bond. Ionic bonding occurs when one atom donates an electron to another, resulting in the formation of ions, as observed in our exercise with potassium and iodine.

The atom that loses an electron becomes a positively charged ion, or cation, and the one that gains an electron becomes a negatively charged ion, or anion. The resulting electrostatic attraction between these oppositely charged ions creates the ionic bond, holding them together within the compound. Ionic bonds are generally formed between metals, which tend to lose electrons, and nonmetals, which tend to gain electrons.

In the case of potassium and iodine, the transfer of an electron from potassium to iodine results in a strong ionic bond, producing a stable ionic compound. This interplay of electron transfer is central to understanding why certain elements form compounds and how the structure of the periodic table influences chemical reactivity.