Question

Based on their location in the periodic table, give the symbols for three elements that would be expected to form positive ions in their reactions.

Short answer

The elements Sodium (Na), Magnesium (Mg), and Iron (Fe) are examples of metals that form positive ions in their reactions. These are represented by the following reactions: 1. Sodium (Na): \(Na \rightarrow Na^+ + e^-\) 2. Magnesium (Mg): \(Mg \rightarrow Mg^{2+} + 2e^-\) 3. Iron (Fe): \(Fe \rightarrow Fe^{2+} + 2e^-\) and \(Fe \rightarrow Fe^{3+} + 3e^-\)

Step-by-step solution

Identify the metals in the periodic table

Metals are the elements found on the left side of the periodic table. They have a few common properties such as high electrical conductivity, malleability, and ductility. Metals are known for losing electrons in their reactions to form positive ions.

Choose three elements from different groups

To provide a diverse set of examples, we will choose one element from each of the following groups: alkali metals (Group 1), alkaline earth metals (Group 2), and transition metals (Groups 3-12). Example 1 - Alkali metal: Sodium (Na) Example 2 - Alkaline earth metal: Magnesium (Mg) Example 3 - Transition metal: Iron (Fe) These elements are expected to form positive ions in their reactions: 1. Sodium (Na): Na -> Na^+ + e^- 2. Magnesium (Mg): Mg -> Mg^2+ + 2e^- 3. Iron (Fe): Fe -> Fe^2+ + 2e^- (Iron can also form a 3+ ion: Fe -> Fe^3+ + 3e^-)

Key concepts

Understanding the Periodic Table

The periodic table is a systematic arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties. Its structure reveals much about an element's characteristics and how it will behave in chemical reactions. Elements are grouped into rows called periods and columns known as groups or families.

On the periodic table, metals are primarily found on the left side and in the middle. They are typically lustrous, ductile, and good conductors of heat and electricity. This makes metals distinct from nonmetals, which are found on the right side of the table. The metals' propensity to lose electrons and form positive ions—also known as cations—is a key trait that is instrumental in understanding chemical reactivity and bonding patterns.

Metals and Their Tendency to Form Positive Ions

Metals, characterized by their ability to conduct electricity, bend without breaking, and shine when polished, are also chemically prone to lose electrons. This behavior can be attributed to their atomic structure: metals have relatively few electrons in their outermost shell, which can be easily removed. When a metal atom loses one or more valence electrons, it becomes a positively charged ion, often referred to as a cation.

This process is essential in understanding the metal's reactivity. For instance, alkali metals in Group 1, such as sodium (Na), lose one electron to form a 1+ ion. Alkaline earth metals in Group 2, like magnesium (Mg), lose two electrons to form a 2+ ion, and transition metals, such as iron (Fe), can lose two or three electrons to form 2+ or 3+ ions, respectively. The charge on the ion corresponds to the number of electrons lost, which is reflected in the element's position on the periodic table.

Chemical Reactions and the Formation of Positive Ions

In the scope of chemical reactions, the formation of positive ions is a common occurrence, especially involving metallic elements. These transformations happen because atoms strive to achieve a stable electronic configuration, often resembling the nearest noble gas atom. Metals, having fewer valence electrons, tend to lose these easily to attain such stability, and the loss of electrons results in the creation of positive ions.

Reflecting on our examples, the reaction for sodium forming a positive ion can be expressed as: \( Na \rightarrow Na^+ + e^- \). Similarly, magnesium forms a 2+ ion: \( Mg \rightarrow Mg^2+ + 2e^- \), and iron forms 2+ and 3+ ions: \( Fe \rightarrow Fe^2+ + 2e^- \) or \( Fe \rightarrow Fe^3+ + 3e^- \). Each electron loss corresponds to a step towards attaining stability. These principles help us predict and understand the numerous reactions metals can participate in, from the simple to the complex.