Group-wise Ionic Radii
Group 1: Alkali Metals (Cations)
- Atomic Number 3: Li⁺ - 76 pm
- Atomic Number 11: Na⁺ - 102 pm
- Atomic Number 19: K⁺ - 138 pm
- Atomic Number 37: Rb⁺ - 152 pm
- Atomic Number 55: Cs⁺ - 167 pm
- Atomic Number 87: Fr²⁺ - 270 pm (estimated)
Group 2: Alkaline Earth Metals (Cations)
- Atomic Number 4: Be²⁺ - 45 pm
- Atomic Number 12: Mg²⁺ - 72 pm
- Atomic Number 20: Ca²⁺ - 100 pm
- Atomic Number 38: Sr²⁺ - 113 pm
- Atomic Number 56: Ba²⁺ - 114 pm
- Atomic Number 88: Ra²⁺ - 130 pm (estimated)
Group 13: Boron Group (Cations)
- Atomic Number 5: B³⁺ - 27 pm (very small)
- Atomic Number 13: Al³⁺ - 53 pm
- Atomic Number 31: Ga³⁺ - 135 pm
- Atomic Number 49: In³⁺ - 100 pm
- Atomic Number 81: Tl³⁺ - 156 pm
Group 14: Carbon Group (Cations)
- Atomic Number 6: C⁴⁻ - 182 pm (as carbide, larger anion)
- Atomic Number 14: Si⁴⁺ - 40 pm
Group 15: Nitrogen Group (Anions and Cations)
- Atomic Number 7: N³⁻ - 140 pm
- Atomic Number 15: P³⁻ - 175 pm
- Atomic Number 33: As³⁻ - 197 pm
Group 16: Chalcogens (Anions)
- Atomic Number 8: O²⁻ - 140 pm
- Atomic Number 16: S²⁻ - 184 pm
- Atomic Number 34: Se²⁻ - 198 pm
- Atomic Number 52: Te²⁻ - 206 pm
- Atomic Number 86: Po²⁻ - 150 pm (estimated)
Group 17: Halogens (Anions)
- Atomic Number 9: F⁻ - 133 pm
- Atomic Number 17: Cl⁻ - 181 pm
- Atomic Number 35: Br⁻ - 196 pm
- Atomic Number 53: I⁻ - 220 pm
- Atomic Number 85: At⁻ - 202 pm (estimated)
Summary
- Cations (from Groups 1, 2, 13, and some in 14 and 15) typically have smaller ionic radii compared to their neutral atoms due to the loss of electrons.
- Anions (from Groups 15, 16, and 17) have larger ionic radii due to the gain of electrons.
These values are approximate and can vary based on specific compounds and conditions.
| Atomic Number | Element | Ionic Radius (pm) |
|---|
| 114 | Fl | 180 (Fl⁴⁺
| Atomic Number | Element | Ionic Radius (pm) |
|---|
| 4 | Beryllium (Be) | 112 (Be²⁺) |
| 12 | Magnesium (Mg) | 160 (Mg²⁺) |
| 13 | Aluminum (Al) | 143 (Al³⁺) |
| 15 | Phosphorus (P) | 110 (P³⁻) |
| 21 | Scandium (Sc) | 162 (Sc³⁺) |
| 22 | Titanium (Ti) | 147 (Ti⁴⁺) |
| 24 | Chromium (Cr) | 133 (Cr³⁺) |
| 25 | Manganese (Mn) | 120 (Mn²⁺) |
| 32 | Germanium (Ge) | 124 (Ge⁴⁺) |
| 34 | Selenium (Se) | 116 (Se²⁻) |
| 38 | Strontium (Sr) | 215 (Sr²⁺) |
| 40 | Zirconium (Zr) | 160 (Zr⁴⁺) |
| 42 | Molybdenum (Mo) | 139 (Mo³⁺) |
| 43 | Technetium (Tc) | 136 (Tc⁷⁺) |
| 44 | Ruthenium (Ru) | 127 (Ru⁴⁺) |
| 46 | Palladium (Pd) | 125 (Pd²⁺) |
| 51 | Antimony (Sb) | 133 (Sb³⁻) |
| 52 | Tellurium (Te) | 134 (Te²⁻) |
| 57 | Lanthanum (La) | 126 (La³⁺) |
| 59 | Praseodymium (Pr) | 108 (Pr³⁺) |
| 60 | Neodymium (Nd) | 106 (Nd³⁺) |
| 61 | Promethium (Pm) | 103 (Pm³⁺) |
| 64 | Gadolinium (Gd) | 93 (Gd³⁺) |
| 66 | Dysprosium (Dy) | 89 (Dy³⁺) |
| 70 | Ytterbium (Yb) | 83 (Yb³⁺) |
| 73 | Tantalum (Ta) | 146 (Ta⁵⁺) |
| 78 | Platinum (Pt) | 133 (Pt²⁺) |
| 81 | Thallium (Tl) | 156 (Tl³⁺) |
| 84 | Polonium (Po) | 135 (Po²⁻) |
| 89 | Actinium (Ac) | 186 (Ac³⁺) |
| 91 | Protactinium (Pa) | 187 (Pa⁴⁺) |
| 93 | Neptunium (Np) | 193 (Np⁶⁺) |
|