The 3p subshell has three degenerate orbitals; according to Hund's Rule, they fill singly before pairing. A 3p3 configuration results in three unpaired electrons.
Metallic bonding is due to the electrostatic attraction between metal cations and delocalized electrons, forming a metal lattice without creating a new chemical compound.
Ammonium ion forms via dative (coordinate) covalent bonding when nitrogen donates its lone pair to hydrogen.
Reactions and Stoichiometry
Reaction rates are influenced by factors like surface area and temperature. Smaller particles increase area, speeding reactions.
Hydrolysis in acidic solutions breaks proteins into amino acids, while combustion produces water and carbon dioxide.
The balanced chemical equation satisfies the Law of Conservation of Mass.
Gases and the Ideal Gas Law
The ideal gas law correlates pressure, volume, and moles; halving the amount of gas reduces pressure at constant volume and temperature.
Dalton's Law states the total pressure of a gas mixture equals the sum of partial pressures.
Separation Techniques and Mixtures
Chromatography separates mixtures based on different migration rates across stationary and mobile phases.
Fractional distillation separates gases based on differing boiling points.
Mixtures, like seawater, do not have a fixed composition and are physically combined.
Acids, Bases, and Neutralization
Acid-base neutralization involves reactions that yield water and salts; strength is measured by ionization extent in water.
Solutions like NaOH can be neutralized with HCl, and the calculation of required volumes uses molarity equations.
Chemical Data and Measurements
The concentration (mol/dm³) is calculated by dividing the number of moles by volume in dm³.
Molar mass can be derived from mass and mole relationships.
Thermodynamics and Energy Changes
Activation energy is the minimal energy for reactants to form products. Gibbs' free energy assesses spontaneity in reactions.
Endothermic processes absorb heat, while exothermic ones release heat, relevant in dissolution and reactions.
Solutions and Solubility
The solubility of ionic compounds often increases with temperature, reflecting Le Chatelier's principle in dynamic equilibria.
Deliquescent substances absorb moisture from the air, aiding in forming solutions.
Organic Chemistry
Alkanes are saturated hydrocarbons, while primary and secondary alcohols undergo distinct oxidation processes (primary to aldehydes, secondary to ketones).
Isomerism, particularly cis-trans, is influenced by restricted rotation around double bonds.
Chemical Safety and Environmental Impact
Safe first-aid for acid spills includes flushing with water to dilute harmful substances.
Pollutants like CFCs contribute to ozone layer depletion, highlighting the need for responsible chemical use in industry and beyond.