JAMB Chemistry 2015 Paper

Concept:The orbital diagram shown represents the distribution of electrons in the energy levels and sublevels of an atom.Explanation:The atom with atomic number $7$ has the electronic configuration $1s^2 \, 2s^2 \, 2p^3$. This means its $2p$ sublevel contains three electrons, each occupying a separate orbital with parallel spins. An orbital diagram with three half-filled $2p$ orbitals matches this configuration. Among the options, nitrogen has atomic number $7$ and exactly this electronic configuration. Chlorine ($17$), calcium ($20$), and neon ($10$) do not match this diagram.Answer:B. nitrogen