Li-ion batteries exploit the low IE and small atomic radius of lithium (s-block, Group 1, Period 2). Easy oxidation of Li metal drives electrochemical reactions.

Hall–Héroult process (aluminium smelting): $Al_{2}O_{3}$ is amphoteric (diagonal relationship to Be), which allows it to dissolve in molten cryolite and be electrolytically reduced to Al metal.

Chlorine water disinfection: $Cl_{2}$ (d-block neighbor via halogen family, high EGE) is an excellent oxidant and electron acceptor, used to eliminate pathogens in municipal water treatment.

Teflon (PTFE): Built on C–F bonds, exploiting fluorine's extreme electronegativity (4.0) and the resulting bond stability and non-reactivity.

Aerospace alloys (Mg–Li): Diagonal relationship between Li and Mg gives Mg–Li alloys a low density and good mechanical strength, vital in aircraft manufacturing.

Ozone depletion: Cl radicals from photolysis of CFCs exploit Cl's high electron affinity (most negative EGE among halogens) to abstract O from $O_{3}$ in a chain mechanism.

Barium sulfate ($BaSO_{4}$) in X-ray imaging: $Ba^{2+}$ has a large ionic radius (s-block, Group 2) and high electron density, making it opaque to X-rays. Used as contrast agent in gastrointestinal imaging.

Fireworks colors: $Sr^{2+}$ (Group 2, large ionic radius) produces crimson flames; electronegativity and ionic size dictate flame-test colors across Group 2 elements.

Fluorosis and fluoride toxicity: Environmental fluoride contamination causes dental/skeletal fluorosis. F's extreme reactivity (highest EN, strong oxidant) makes high concentrations harmful.

Variable oxidation states of d-block metals: Transition metals like Cr, Mn, and Fe can exist in multiple oxidation states because electrons in the (n−1)d subshell are close in energy to those in the ns subshell. This is exploited in industrial catalysis (Fe in Haber process, $V_{2}O_{5}$ in Contact process).