Periodic Table Trends & Group Properties: Ionization, Atomic & Ionic Radii, Reactivity

Ionization Energy

Top → Bottom: ⬇️ Decreases — outer electrons easier to remove.

Left → Right: ⬆️ Increases — nucleus pulls electrons tighter.

Atomic Radius / Size

Top → Bottom: ⬆️ Increases — more shells.

Left → Right: ⬇️ Decreases — nucleus pulls electrons in.

Ionic Radius

Top → Bottom: ⬆️ Increases — ions gain shells.

Left → Right: ⬇️ Decreases — higher nuclear charge shrinks ions.

Electronegativity

Top → Bottom: ⬇️ Decreases — big atoms attract electrons less.

Left → Right: ⬆️ Increases — stronger nuclear pull attracts electrons more.

Alkali Metals (Group 1)

⚡ Very reactive with water;

➕1 ions formed;

🔥 Soft metals, tarnish fast.

Alkaline Earth Metals (Group 2)

⚡ Reactive (less than Group 1);

➕2 ions formed;

⚙️ Harder, higher melting points.

Transition Metals (Groups 3-12)

⚖️ Moderate reactivity;

➕ multiple ions;

🔧 Colored compounds, good conductors.

Halogens (Group 17)

💥 Very reactive nonmetals;

➖1 ions formed;

☣️ Toxic, gases/liquids/solids.

Noble Gases (Group 18)

🧊 Nonreactive;

❌ Form no ions;

💨 Colorless gases, stable.

Metalloids

⚖️ Moderate/variable reactivity;

🔺 Semi-conductors;

🔁 Between metals and nonmetals.

Nonmetals

⚠️ Varies in reactivity;

💨 Poor conductors;

🧪 Form covalent bonds easily.

Other Metals

🧪 Form positive ions
⚠ Low to moderate reactivity
✨ Shiny metallic appearance

Lanthanides

💡 Reactive metals;

✨ Bright-colored compounds;

🧲 Used in magnets, electronics.

Actinides

☢️ Very reactive;

🔥 Mostly radioactive;

⚛️ Many are synthetic.