Neon vs Argon
Neon and Argon sit in the same column of the periodic table — same family, one period apart — so almost every difference between them comes from one thing: the extra electron shell Argon wears.
Side by side
| Property | Neon | Argon |
|---|---|---|
| Symbol | Ne | Ar |
| Atomic number (Z) | 10 | 18 |
| Atomic mass | 20.180 u | 39.95 u |
| Category | Noble gas | Noble gas |
| Group | 18 | 18 |
| Period | 2 | 3 |
| Phase at room temp | gas | gas |
| Electron configuration | [He] 2s^2 2p^6 | [Ne] 3s^2 3p^6 |
| Valence electrons | 8 | 8 |
| Atomic radius | 38 pm | 71 pm |
| Electronegativity | — | — |
| First ionisation energy | 2081 kJ/mol | 1521 kJ/mol |
The verdicts
- Bigger atom: Argon — the lower an element sits in its group, the more shells it wears.
- Greedy electron-taker: Neon — higher electronegativity means it pulls shared electrons harder.
- Heavier: Argon — compare the atomic masses in the table above.
Want the visual version with bars for radius, electronegativity and ionisation energy? Open the interactive compare tool with this pair already loaded.