Question

Discussing this chapter, a classmate says, "An element that commonly forms a cation is a metal." Do you agree or disagree?

Short answer

I agree with the classmate's statement. Metals tend to lose their valence electrons easily during chemical reactions, which makes them prone to forming positively charged ions (cations). Characteristics such as being found on the left side of the periodic table, high melting points, high boiling points, malleability, electrical conductivity, and reactivity with nonmetals support this assertion.

Step-by-step solution

Understanding Cations and Metals

A cation is a positively charged ion, meaning it has lost one or more electrons. Metals, as elements, tend to have a few electrons in their outermost energy level (valence electrons) and tend to lose these electrons easily during chemical reactions. This property of metals makes them good candidates for forming cations.

Identifying Metal Characteristics

Metals are typically found on the left side of the periodic table and have properties such as high melting points, high boiling points, malleability, electrical conductivity, and reactivity with nonmetals. When metals react with nonmetals, they tend to lose their valence electrons and form positive ions (cations).

Evaluating the Statement

The statement made by the classmate is "An element that commonly forms a cation is a metal." Based on our understanding of metals and cations, we can see that metals have the tendency of forming cations due to their ability to lose valence electrons easily during chemical reactions.

Conclusion

In conclusion, we can agree with the classmate's statement – elements that commonly form cations are usually metals, as metals have properties and characteristics that make them prone to forming positively charged ions (cations) during chemical reactions with nonmetals.

Key concepts

Valence Electrons

Understanding valence electrons is essential to grasping basic chemistry concepts, especially when tackling exercises related to cations and metals. Valence electrons are the electrons in the outermost shell of an atom and play a pivotal role in chemical reactions. They are significant because their presence determines an atom's ability to bond with other atoms.

For metals, which are mostly found on the left side and in the center of the periodic table, they often have one, two, or three valence electrons. These are somewhat loosely held within the atom and can be easily lost. When a metal atom loses its valence electrons, it becomes a positively charged ion, known as a cation. This ability to lose electrons easily is what makes metals good conductors of electricity and prone to forming cations in chemical reactions.

For instance, sodium (Na) has one valence electron in its outermost shell. During a reaction, it can easily lose this electron to become sodium cation (Na+). This property is not only key to understanding cations formation but indeed all of chemistry, as valence electrons are at the heart of chemical bonding and reactions.

Periodic Table

The periodic table is more than just an arrangement of elements; it's a map of chemical properties, including trends in the behavior of their valence electrons. Elements are organized by increasing atomic number, with metals positioned to the left and towards the bottom of the table. This location is not random—it reflects the elements' tendency to lose valence electrons and form cations.

Looking at the periodic table, the vertical columns, known as groups, have elements with the same number of valence electrons, which means they show similar properties during chemical reactions. Horizontal rows, called periods, indicate the energy level of valence electrons for elements in that row. As you move from left to right across a period, the number of valence electrons generally increases, which affects how easily an element can lose electrons and form cations.

For example, group 1 elements, also known as alkali metals, have one valence electron and are highly reactive. They readily lose that single electron to form cations, such as in the case of potassium (K) becoming a potassium ion (K+). Understanding these trends and the layout of the periodic table enables students to predict and comprehend how elements, particularly metals, will behave in chemical reactions.

Chemical Reactions

Chemical reactions are processes where substances (reactants) convert into new substances (products) with different properties. During these reactions, valence electrons are exchanged, shared or redistributed among atoms, leading to the formation of ions and other chemical compounds. For metals, these reactions typically entail the loss of valence electrons and the consequent formation of cations.

Let's use sodium chloride (table salt) formation as an example: sodium (Na) reacts with chlorine (Cl), transferring its valence electron to chlorine. Sodium loses an electron and forms a Na+ cation, while chlorine gains an electron to become a chloride anion (Cl-). This transfer of electrons is a classic example of a type of chemical reaction known as ionic bonding. In general, metals will react with nonmetals to form ionic compounds by the transfer of electrons, resulting in positive and negative ions that attract each other to form the compound.

The reactivity of metals and their capacity to form cations is vastly explored during chemical reactions, and understanding this interplay is foundational for students. Knowledge about how valence electrons behave is key to predicting the outcomes of chemical reactions, enabling the solving of exercises related to the properties and tendencies of various elements.