Chapter 2 - Section 2.1 - Study Guide - Assess Your Learning Outcomes - Page 74: 5

**Difference Between an Ion and an Atom**: An ion and an atom are related but have distinct differences: 1. **Atom**: An atom is the basic unit of matter and consists of three subatomic particles: protons, neutrons, and electrons. It is electrically neutral, meaning the number of protons (positively charged) in the nucleus is equal to the number of electrons (negatively charged) orbiting the nucleus. 2. **Ion**: An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net electrical charge. Ions are not electrically neutral due to the imbalance between the number of protons and electrons. **How Ions Form**: Ions form through a process called ionization, which involves the addition or removal of electrons from an atom or molecule. This can happen in several ways: 1. **Ionic Bonding**: Ions are often formed through chemical reactions between atoms. When atoms with different electronegativities come together, one atom may transfer electrons to the other. This transfer creates positively charged ions (cation) and negatively charged ions (anion), which are attracted to each other due to electrostatic forces. For example, sodium (Na) donates an electron to chlorine (Cl) to form the sodium ion (Na+) and chloride ion (Cl-), resulting in table salt (NaCl). 2. **Electron Gain or Loss**: Atoms can also become ions by gaining or losing electrons on their own. When an atom gains an electron, it becomes negatively charged (anion). Conversely, when it loses an electron, it becomes positively charged (cation). For instance, oxygen (O) can gain two electrons to become the oxide ion (O2-). **Two Types of Ions**: 1. **Cations**: Cations are positively charged ions. They form when an atom loses one or more electrons. Common examples include: - **Sodium ion (Na+)**: Formed when a sodium atom loses one electron. - **Potassium ion (K+)**: Formed when a potassium atom loses one electron. - **Magnesium ion (Mg2+)**: Formed when a magnesium atom loses two electrons. 2. **Anions**: Anions are negatively charged ions. They form when an atom gains one or more electrons. Common examples include: - **Chloride ion (Cl-)**: Formed when a chlorine atom gains one electron. - **Sulfate ion (SO4^2-)**: Formed when a sulfur atom gains two electrons and is bonded to four oxygen atoms. - **Nitrate ion (NO3-)**: Formed when a nitrogen atom gains one electron and is bonded to three oxygen atoms. Ions are essential in various chemical and biological processes. They play roles in chemical reactions, electrical conductivity in solutions, nerve impulses, and muscle contractions, among other functions. The ability of ions to carry electrical charges makes them critical to many aspects of chemistry and biology.

**Difference Between an Ion and an Atom**: An ion and an atom are related but have distinct differences: 1. **Atom**: An atom is the basic unit of matter and consists of three subatomic particles: protons, neutrons, and electrons. It is electrically neutral, meaning the number of protons (positively charged) in the nucleus is equal to the number of electrons (negatively charged) orbiting the nucleus. 2. **Ion**: An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net electrical charge. Ions are not electrically neutral due to the imbalance between the number of protons and electrons. **How Ions Form**: Ions form through a process called ionization, which involves the addition or removal of electrons from an atom or molecule. This can happen in several ways: 1. **Ionic Bonding**: Ions are often formed through chemical reactions between atoms. When atoms with different electronegativities come together, one atom may transfer electrons to the other. This transfer creates positively charged ions (cation) and negatively charged ions (anion), which are attracted to each other due to electrostatic forces. For example, sodium (Na) donates an electron to chlorine (Cl) to form the sodium ion (Na+) and chloride ion (Cl-), resulting in table salt (NaCl). 2. **Electron Gain or Loss**: Atoms can also become ions by gaining or losing electrons on their own. When an atom gains an electron, it becomes negatively charged (anion). Conversely, when it loses an electron, it becomes positively charged (cation). For instance, oxygen (O) can gain two electrons to become the oxide ion (O2-). **Two Types of Ions**: 1. **Cations**: Cations are positively charged ions. They form when an atom loses one or more electrons. Common examples include: - **Sodium ion (Na+)**: Formed when a sodium atom loses one electron. - **Potassium ion (K+)**: Formed when a potassium atom loses one electron. - **Magnesium ion (Mg2+)**: Formed when a magnesium atom loses two electrons. 2. **Anions**: Anions are negatively charged ions. They form when an atom gains one or more electrons. Common examples include: - **Chloride ion (Cl-)**: Formed when a chlorine atom gains one electron. - **Sulfate ion (SO4^2-)**: Formed when a sulfur atom gains two electrons and is bonded to four oxygen atoms. - **Nitrate ion (NO3-)**: Formed when a nitrogen atom gains one electron and is bonded to three oxygen atoms. Ions are essential in various chemical and biological processes. They play roles in chemical reactions, electrical conductivity in solutions, nerve impulses, and muscle contractions, among other functions. The ability of ions to carry electrical charges makes them critical to many aspects of chemistry and biology.