Question

Determine the charge of each ion. (a) oxygen ion with 10 electrons (b) aluminum ion with 10 electrons (c) titanium ion with 18 electrons (d) iodine ion with 54 electrons

Short answer

The charge of each ion is (a) -2, (b) +3, (c) +4, (d) -1.

Step-by-step solution

Identifying the Charge of an Oxygen Ion with 10 Electrons

To identify the charge of an oxygen ion, you need to know the number of protons in an oxygen atom, which is 8 (its atomic number). Normally, oxygen has 8 electrons, but in this case, it has 10. The extra 2 electrons mean it has a charge of -2, since each electron adds a negative charge.

Determining the Charge of an Aluminum Ion with 10 Electrons

An aluminum atom normally has 13 protons, and therefore 13 electrons to be neutral. With only 10 electrons, it is missing 3, which means it has a charge of +3 (positive because it has lost electrons).

Calculating the Charge of a Titanium Ion with 18 Electrons

A titanium atom has 22 protons. For the ion to have 18 electrons, it is missing 4 electrons compared to a neutral atom, giving it a charge of +4.

Figuring Out the Charge of an Iodine Ion with 54 Electrons

An iodine atom normally has 53 protons. If the iodine ion has 54 electrons, it has one extra electron, giving it a charge of -1.

Key concepts

Chemistry and Determining Ion Charge

In chemistry, understanding the charge of ions is fundamental to grasping how atoms interact to form compounds. Ions are atoms or molecules that have lost or gained electrons, resulting in a net electrical charge. During ion formation, an atom becomes positively charged if it loses electrons, known as a cation, or negatively charged if it gains electrons, leading to an anion. For example, considering an aluminum ion with 10 electrons, knowing that an aluminum atom typically possesses 13 electrons, we recognize that the ion is missing 3 electrons and is therefore a cation with a charge of +3.

Understanding the charge of ions is critical for predicting the formulas of ionic compounds, understanding the role of electrolytes in physical processes, and in many other areas of chemistry. The charge directly affects how ions bond and interact, as ions with opposite charges attract and potentially form ionic bonds, a staple in the formation of many compounds.

Ions and Isotopes

Atoms of the same element can exist in different forms called isotopes, which have the same number of protons but different numbers of neutrons. This alters their mass but not their chemical behavior. Unlike isotopes, ions are formed by the loss or gain of electrons which greatly impacts their chemical behavior due to the resulting charge. Isotopes do not have a net charge; their electrical neutrality remains intact. To illustrate, an oxygen atom remains an isotope of oxygen regardless of the number of neutrons, but once it gains or loses electrons—such as the oxygen ion with 10 electrons—it becomes an ion with a charge, specifically, a -2 anion in this case. The distinction between isotopes and ions is crucial in more advanced topics such as nuclear chemistry, where isotopes play a major role, and electrochemistry, which focuses on ion behavior.

Atomic Structure

The atomic structure is the key to determining an ion's charge. The structure includes the nucleus, with protons and neutrons, and the electron cloud with electrons orbiting at various levels. The number of protons (ideally balanced by an equal number of electrons) determines the element's identity and is known as the atomic number. Positive or negative charges are the result of an imbalance between protons and electrons. For instance, a titanium atom having an atomic number of 22 normally carries 22 electrons; however, if it has 18 electrons, like the titanium ion in the exercise, it is deficient by four electrons, indicating a +4 charge. The manipulation of atomic structures through the gain or loss of electrons (ionization) is at the heart of many chemical reactions and technologies, such as batteries and sensors.

Oxidation States

Oxidation states, also referred to as oxidation numbers, are hypothetical charges atoms would have if all bonds were ionic. They are essential for understanding the electron transfer in reactions, particularly in redox (oxidation-reduction) reactions. In the context of the given exercise, the oxidation state represents the charge of each ion. By examining the iodine ion with 54 electrons, we can deduce its oxidation state. As an iodine atom typically carries 53 electrons, the additional electron increases its oxidation state to -1, making it an anion. The oxidation state is instrumental for balancing chemical equations and determining the roles of different atoms within chemical compounds. It's also used as a communicating tool among chemists to describe the electron distribution within molecules.