Chemistry · Ch 2 — p-Block Elements-I
Physical Properties
2.2.2
Physical Properties
Table 2.3 tabulates the core physical properties of the five group 13 elements. All five are solids at 293 K. Atomic number rises from 5 (boron) to 81 (thallium); boron's single stable isotope is ¹¹B, and the other members likewise have one dominant isotope (²⁷Al, ⁶⁹Ga, ¹¹⁵In, ²⁰⁵Tl). Every member has the outer electronic configuration ns²np¹, with an increasingly filled d and f core beneath it from gallium onward ([Ar]3d¹⁰4s²4p¹ for Ga, adding [Kr]4d¹⁰ for In, and [Xe]4f¹⁴5d¹⁰ for Tl) -- exactly the poorly-shielding inner electrons responsible for the ionisation-enthalpy anomaly of Section 2.1.3. …
Table 2.3Physical properties of group 13 elements
| Property | Boron | Aluminium | Gallium | Indium | Thallium |
|---|---|---|---|---|---|
| Physical state at 293 K | Solid | Solid | Solid | Solid | Solid |
| Atomic Number | 5 | 13 | 31 | 49 | 81 |
| Isotopes | ¹¹B | ²⁷Al | ⁶⁹Ga | ¹¹⁵In | ²⁰⁵Tl |
| Atomic Mass (g mol⁻¹ at 293 K) | 10.81 | 26.98 | 69.72 | 114.81 | 204.38 |
| Electronic configuration | [He]2s²2p¹ | [Ne]3s²3p¹ | [Ar]3d¹⁰4s²4p¹ | [Kr]4d¹⁰5s²5p¹ | [Xe]4f¹⁴5d¹⁰6s²6p¹ |
| Atomic radius (Å) | 1.92 | 1.84 | 1.87 | 1.93 | 1.96 |
| Density (g cm⁻³ at 293 K) | 2.34 | 2.70 | 5.91 | 7.31 | 11.80 |