(c) hydrogen fluoride, HF , or hydrogen chloride, A. Consider the following substances: sodium fluoride \( (\mathrm{NaF}) \), chlorine monoruc hydrogen fluoride (HF), and fluorine ( \( \mathrm{F}_{2} \) ). (a) What type of particles does each substance have? (b) What type of intermolecular attractive forces hold the particles together in each substance?

Certainly! Let's analyze each of the given substances—**sodium fluoride (NaF)**, **hydrogen fluoride (HF)**, and **fluorine (F₂)**—in terms of the **types of particles** they consist of and the **intermolecular forces** that hold these particles together. --- ### **a. Types of Particles** 1. **Sodium Fluoride (NaF)** - **Type of Particle:** **Ionic Compound** - **Structure:** Consists of **ions**—specifically, positively charged sodium ions (**Na⁺**) and negatively charged fluoride ions (**F⁻**) arranged in a **crystalline ionic lattice**. 2. **Hydrogen Fluoride (HF)** - **Type of Particle:** **Molecular Compound** - **Structure:** Composed of discrete **HF molecules**, each containing one hydrogen atom covalently bonded to one fluorine atom. 3. **Fluorine (F₂)** - **Type of Particle:** **Molecular Substance** - **Structure:** Exists as **diatomic molecules** (**F₂**), where two fluorine atoms are covalently bonded together. --- ### **b. Types of Intermolecular Attractive Forces** 1. **Sodium Fluoride (NaF)** - **Intermolecular Forces:** **Ionic Bonds** - **Description:** The **electrostatic attraction** between the **Na⁺** and **F⁻** ions forms a **strong ionic lattice**. These bonds are **intramolecular** (within the compound) rather than intermolecular (between separate molecules), meaning they hold the entire crystal structure together rather than individual molecules. 2. **Hydrogen Fluoride (HF)** - **Intermolecular Forces:** **Hydrogen Bonds** and **Dipole-Dipole Interactions** - **Description:** - **Hydrogen Bonding:** Due to the high electronegativity of fluorine, HF molecules are highly polar, enabling the formation of **hydrogen bonds** where the hydrogen atom of one HF molecule is attracted to the lone pair of electrons on the fluorine atom of another HF molecule. - **Dipole-Dipole Interactions:** The polarity of HF molecules also leads to **dipole-dipole attractions**, where positive and negative ends of different molecules attract each other. 3. **Fluorine (F₂)** - **Intermolecular Forces:** **London Dispersion Forces (Van der Waals Forces)** - **Description:** F₂ molecules are **nonpolar** because the two fluorine atoms share electrons equally. The primary intermolecular force here is **London dispersion forces**, which are temporary, induced dipoles that occur due to the momentary distribution of electrons within the molecules. These forces are relatively **weak** compared to hydrogen bonds and ionic bonds. --- ### **Summary Table** | **Substance** | **Type of Particles** | **Intermolecular Forces** | |-----------------|-----------------------|---------------------------------------------| | **NaF** | Ionic Compound | Ionic Bonds (Electrostatic attractions) | | **HF** | Molecular Compound | Hydrogen Bonds, Dipole-Dipole Interactions | | **F₂** | Molecular Substance | London Dispersion Forces | --- ### **Key Points to Remember** - **Ionic Compounds** like NaF are composed of ions held together by strong **ionic bonds**. These do not consist of discrete molecules but rather a continuous lattice structure. - **Molecular Compounds** like HF consist of individual molecules held together by **hydrogen bonds** and **dipole-dipole interactions** if they are polar. - **Nonpolar Molecular Substances** like F₂ are held together primarily by **London dispersion forces**, which are the weakest type of intermolecular force. Understanding the nature of particles and the intermolecular forces at play helps explain the physical properties of these substances, such as melting and boiling points, solubility, and electrical conductivity. ---