This section details the Differences between atomic radius and ionic radius in chemistry and explores covalent bonding concepts.

Definition: Atomic radius is the distance from an atom's nucleus to its outermost electron shell.

Highlight: Atomic radius trends are influenced by two main factors:

• Increases down a group due to additional electron shells
• Decreases across a period due to increased nuclear attraction

Example: Molecular structures like H₂, N₂, O₂, F₂, Cl₂, Br₂, and I₂ demonstrate covalent bonding principles.

Vocabulary:

• Ionic radius: The size of an ion after gaining or losing electrons
• Covalent radius: Half the distance between nuclei in a covalently bonded molecule
• Cation: Positively charged ion formed by losing electrons
• Anion: Negatively charged ion formed by gaining electrons

The section explains how ionic radii differ from atomic radii:

• Cations are smaller than their parent atoms
• Anions are larger than their parent atoms due to increased electron repulsion

This section explores the fundamental concepts of nuclear chemistry and radioactive processes. The content covers essential aspects of radioactive decay, nuclear reactions, and various types of radiation.

Definition: Radioactivity is the spontaneous breakdown of unstable nuclei until they become stable, accompanied by the emission of radiation.

Highlight: All nuclear reactions are exothermic, releasing energy through radiation during nuclear decay processes.

Example: Common radioisotopes include C-14, O-18, and K-42, which have different proton-to-neutron ratios than stable isotopes.

Vocabulary:

• Radioisotope: Unstable atomic nuclei with an unbalanced proton-to-neutron ratio
• Nuclear reaction: Process involving changes in atomic nuclei, accompanied by energy release
• Transmutation: The conversion of one element into another through nuclear processes

The section details various types of radiation particles, including:

• Alpha particles (α): Helium nuclei with mass 4 and charge +2
• Beta particles (β): Electrons or positrons with minimal mass
• Gamma radiation (γ): High-energy electromagnetic waves with no mass or charge