--- ### ✅ **def mass_number():** A = Z + N - **A** = mass number - **Z** = number of protons - **N** = number of neutrons --- ### ✅ **def atomic_weight():** Atomic_Weight = NA × weight_per_atom - NA = Avogadro's number = 6.022 × 1023 atoms/mol --- ### ✅ **def electron_config(element):** → Defined by quantum numbers: - **n**: principal level - **l**: subshell (s, p, d, f) - **ml**: orbital orientation - **ms**: spin (+1⁄2, -1⁄2) Electrons fill orbitals by increasing energy levels (Aufbau principle). --- ### ✅ **def electronegativity():** - Ranges from 0.7 to 4.0 - High electronegativity → tendency to gain electrons - Used to predict bonding type --- ### ✅ **def ionic_bonding():** Occurs when electrons are **transferred** → Between **metal (low EN)** and **non-metal (high EN)** → Example: NaCl, MgO --- ### ✅ **def covalent_bonding():** Occurs when electrons are **shared** → Between atoms with **similar electronegativity** → Example: CH4, O2 --- ### ✅ **def metallic_bonding():** Delocalized “electron cloud” around positive metal ions → Non-directional, explains conductivity and malleability in metals --- ### ✅ **def secondary_bonding():** Weak interactions between molecules - **Dipole-dipole** - **Induced dipoles** - **London dispersion forces** → Example: polymers, HCl, water --- ### ✅ **def net_bond_energy():** EN = -A / r + B / rn - EN = net energy - A = attractive constant - B, n = repulsive constants - r = interatomic separation --- ### ✅ **def bond_properties():** - **Bond length (r0)**: equilibrium distance - **Bond energy (E0)**: energy to separate atoms → Higher E0 → Higher melting temperature → Lower E0 → Higher thermal expansion --- ### ✅ **def percent_ionic_character():** %IC ≈ [1 - exp(-0.25 * (χ_A - χ_B)2)] × 100 - χ_A, χ_B = electronegativities of atoms A and B --- ### ✅ **def thermal_expansion():** α = ΔL / (L0 * ΔT) - α = coefficient of thermal expansion - Related to **asymmetry** of energy curve --- ### ✅ **Bond Type Summary** | Bond Type | Electron Behavior | Directionality | Strength | Examples | |------------------|----------------------|---------------------|--------------|---------------| | **Ionic** | Transferred | Non-directional | Strong | NaCl, MgO | | **Covalent** | Shared | Directional | Strong–Weak | CH4, Si, C | | **Metallic** | Delocalized cloud | Non-directional | Moderate | Fe, Al | | **Secondary** | Dipoles, van der Waals| Directional (weak) | Weak | Polymers, H2O | --- Let me know if you'd like this merged with previous chapters into one clean PDF or printable booklet!