Understanding the scientific rationale behind Cobalt's position in the periodic table:
Belongs to Group 9 because it has 9 valence electrons (3d⁷ 4s²).
Belongs to Period 4 because its valence electrons fill shell n=4.
Belongs to the d-block because its valence subshell is 3d.
Classified as a transition metal with strong ferromagnetism (Curie temp 1,115 °C).
Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.
Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.
Neutral ground state configuration. Valence electrons: 9.
Mined largely as a byproduct of copper and nickel ores, with over 70% of global supply originating from the Democratic Republic of Congo.
From German 'Kobold' meaning goblin or evil earth spirit, blamed by miners for toxic arsenic fumes
Cobalt dust is a respiratory sensitizer causing occupational asthma and hard-metal lung disease.