First ionisation enthalpy vs atomic number (Z = 1–20)प्रथम आयनन एन्थैल्पी बनाम परमाणु क्रमांक (Z = 1–20)

NCERT Fig 3.5 · interactive diagram

Parts and their functions

• Peaks: noble gases (शिखर: उत्कृष्ट गैसें) — He 2372, Ne 2081, Ar 1521 kJ mol⁻¹ — completely filled shells are very stable.
• Minima: alkali metals (न्यूनतम: क्षार धातुएँ) — Li 520, Na 496, K 419 — a single electron outside a noble-gas core, well shielded, easily lost. Values fall down the group.
• Small dips: B < Be, O < N (and Al, S) (छोटी गिरावट: B < Be, O < N (और Al, S)) — B removes a 2p electron (more shielded than 2s); O removes one of a paired 2p electron (repulsion). N’s half-filled 2p³ is extra stable.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 3.5. Report a mistake