Rhenium (Re) - Atomic Structure and Properties

Atomic Model Details

Rhenium (Re) is a chemical element with the following fundamental atomic characteristics:

• Atomic Symbol: Re
• Atomic Number (Z): 75 (Indicates 75 protons in the nucleus)
• Atomic Mass: 186.207 u (unified atomic mass units)
• Protons: 75
• Electrons: 75 (in a neutral atom)
• Neutrons: For the most abundant isotope, ¹⁸⁷Re, the number of neutrons is 187 - 75 = 112.
• Atomic Size:
  • Metallic Radius: 137.5 pm
  • Covalent Radius: 159 pm

Electronic Configuration & Shell Diagram

The arrangement of electrons in the various shells and subshells of a Rhenium atom dictates its chemical behavior.

• Full Electronic Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d⁵
• Condensed Electronic Configuration: [Xe] 4f¹⁴ 5d⁵ 6s²
  • The [Xe] represents the electronic configuration of Xenon, which has 54 electrons.
• Shell Diagram Representation (Electrons per Shell):
  • K-shell (n=1): 2 electrons
  • L-shell (n=2): 8 electrons
  • M-shell (n=3): 18 electrons
  • N-shell (n=4): 32 electrons (2 from 4s, 10 from 3d, 6 from 4p, 14 from 4f)
  • O-shell (n=5): 7 electrons (2 from 5s, 10 from 4d, 6 from 5p, 5 from 5d)
  • P-shell (n=6): 2 electrons (2 from 6s)
  • Note: The 4f subshell fills after 6s and before 5d due to energy considerations, leading to the complex filling pattern of transition metals and inner transition metals.

Periodic Trends

Rhenium’s position in Group 7 (VIIB) and Period 6 of the d-block in the periodic table influences its periodic properties.

• Ionization Enthalpy: The energy required to remove an electron from a gaseous atom.
  • First Ionization Enthalpy: 760 kJ/mol (Relatively high for a metal due to high nuclear charge and effective shielding by filled inner shells).
• Electronegativity (Pauling Scale): The measure of an atom’s ability to attract shared electrons in a chemical bond.
  • Value: 1.9 (Comparable to other heavy transition metals)
• Electron Gain Enthalpy: The energy released when an electron is added to a neutral gaseous atom.
  • Value: -15 kJ/mol (Rhenium does not readily accept electrons, typical for metals, indicating a low affinity for additional electrons).

Key Physical Properties

Rhenium is a rare, heavy, silvery-white transition metal.

• Density: 21.02 g/cm³ (One of the densest elements, second only to osmium and iridium).
• State at STP (Standard Temperature and Pressure): Solid
• Color: Silvery-white, lustrous metal.
• Melting Point: 3186 °C (Extremely high, one of the highest of all elements).
• Boiling Point: 5630 °C (Among the highest known boiling points).