Neodymium (Nd): Atomic Structure & Chemical Properties

Atomic Model Details of Neodymium (Nd)

Neodymium (Nd) is a chemical element with atomic number 60, belonging to the lanthanide series of the f-block elements.

• Atomic Number (Z): 60
  • Protons: 60
  • Electrons: 60 (in a neutral atom)
• Average Atomic Mass: 144.242 u
  • Neutrons: Approximately 84 (calculated from average atomic mass; for the most common isotope, Nd-142, it is 142 - 60 = 82 neutrons).
• Atomic Size:
  • Metallic Radius: 182 pm
  • Ionic Radius (Nd³⁺): 98.3 pm (for coordination number 6)

Electronic Configuration & Shell Diagram

Electronic Configuration

The ground state electronic configuration of Neodymium (Nd) is: [Xe] 4f⁴ 6s²

This configuration indicates that after the stable noble gas core of Xenon ([Xe]), Neodymium has four electrons in the 4f subshell and two electrons in the 6s subshell.

Shell Diagram Representation (Textual)

The distribution of electrons in different principal energy shells (K, L, M, N, O, P) for Neodymium (Z=60) is as follows:

• K-shell (n=1): 2 electrons
• L-shell (n=2): 8 electrons
• M-shell (n=3): 18 electrons
• N-shell (n=4): 22 electrons (comprising 2 in 4s, 6 in 4p, 10 in 4d, and 4 in 4f)
• O-shell (n=5): 8 electrons (comprising 2 in 5s and 6 in 5p)
• P-shell (n=6): 2 electrons (in 6s)

This gives a total of 2 + 8 + 18 + 22 + 8 + 2 = 60 electrons.

Periodic Trends

Ionization Enthalpy

Neodymium, like other lanthanides, exhibits relatively low ionization energies due to the shielding effect of inner electrons and its large atomic size, making it electropositive.

• First Ionization Enthalpy (IE₁): 533.1 kJ/mol
• Second Ionization Enthalpy (IE₂): 1040 kJ/mol
• Third Ionization Enthalpy (IE₃): 2130 kJ/mol

Electronegativity

Neodymium has low electronegativity, characteristic of metals.

• Pauling Electronegativity: 1.14

Electron Gain Enthalpy

Electron gain enthalpy values for highly electropositive metals like Neodymium are generally positive or not typically reported, as they have a strong tendency to lose electrons rather than gain them.

Atomic Radius

• Metallic Radius: 182 pm.
  • Within the lanthanide series, the atomic radius generally decreases gradually from Lanthanum to Lutetium, a phenomenon known as Lanthanide Contraction. This is due to the poor shielding effect of the 4f electrons, leading to a stronger effective nuclear charge pulling the outer electrons closer to the nucleus.

Key Physical Properties

• State at Standard Temperature and Pressure (STP): Solid
• Color: Silvery-white, lustrous metal that rapidly tarnishes to a purplish oxide layer when exposed to air.
• Density: 7.01 g/cm³ (at 20 °C)
• Melting Point: 1021 °C (1294 K)
• Boiling Point: 3074 °C (3347 K)