Question

How is an ion formed? a. by either adding or subtracting protons from the atom b. by either adding or subtracting neutrons from the atom c. by either adding or subtracting electrons from the atom d. all of the above e. two of the above Explain.

Short answer

An ion is formed by either adding or subtracting electrons from an atom, resulting in a net electric charge. When an atom gains electrons, it becomes a negatively charged ion called an anion. When an atom loses electrons, it becomes a positively charged ion called a cation. Therefore, the correct answer is c. by either adding or subtracting electrons from the atom.

Step-by-step solution

Understanding an ion

An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Explaining the formation of ions

An ion is formed by either adding or subtracting electrons from an atom. When an atom gains electrons, it becomes a negatively charged ion called an anion. When an atom loses electrons, it becomes a positively charged ion called a cation. Protons and neutrons are part of the atomic nucleus and do not play a direct role in ion formation, as their addition or removal would result in a different element or isotope, not an ion.

Selecting the correct answer

Based on the explanation of how ions are formed by the addition or subtraction of electrons, the correct answer is: c. by either adding or subtracting electrons from the atom

Key concepts

Ions and Charge

Ions are the result of atoms or molecules that have gained or lost electrons, which gives them a net electric charge. Unlike protons, which determine the element's identity, electron gain or loss alters the charge of an atom without changing its identity as an element. Let's imagine a scenario where we have a neutral atom, which means it has an equal number of protons and electrons. When an atom gains additional electrons, it now has more negative charges than positive charges, resulting in a negative ion. Oppositely, when an atom loses electrons, it has more positive charges than negative, creating a positive ion. This is significant in chemistry as the charge of an ion determines how it will interact with other ions and molecules, which is a fundamental aspect in the study of chemical reactions.

For a comprehensive grasp of ion formation, it is crucial to understand that the net charge of an ion is a balance between the number of protons (positive charges) and electrons (negative charges). It is the loss or gain of electrons that causes this imbalance, thereby forming an ion with a net charge.

Cations and Anions

An understanding of the types of ions is essential, and there are two primary categories: cations and anions. Cations are positively charged ions formed when an atom loses one or more electrons. Consider sodium (Na), which in its neutral state has 11 electrons. If it loses one electron, it becomes Na+, a cation with a +1 charge. The loss of electrons can happen during chemical reactions, such as when sodium reacts with chlorine to form table salt (NaCl).

Conversely, anions are negatively charged ions that result from the gain of electrons. Chlorine (Cl), for instance, with 17 electrons in its neutral form, can gain an electron to become Cl−, an anion with a -1 charge. These charged particles, cations, and anions, are pivotal for the formation of ionic compounds as they attract each other to create stable arrangements due to their opposite charges.

Electron Gain and Loss

The whole concept of ions revolves around the movement of electrons. The complete electron gain or loss is what differentiates ions from isotopes (varying numbers of neutrons) and different elements (varying numbers of protons). When an electron is added to an atom, we observe the formation of an anion while the removal of an electron results in a cation. This process is crucial for numerous natural phenomena and practical applications, such as the generation of electricity in batteries, where ions move between electrodes to create an electric current.

It is also worth mentioning that the electron configurations, or the arrangement of electrons around the nucleus, will influence an atom's tendency to gain or lose electrons. Atoms seek to reach a stable configuration, often resembling the nearest noble gas, by gaining or losing electrons, thus forming ions. This drive toward stability is a key factor in predicting and understanding chemical reactions.