9.3.2—The nature, possible position in the Periodic

An unknown element can be located by combining periodic-table position clues with measured properties such as ionisation energy, atomic radius, bonding or reactions.

First identify the likely group/period from the strongest evidence, then check whether the proposed element’s structure and reactions fit. Do not force one measurement to decide everything.

A large jump after two successive ionisation energies suggests two valence electrons; if the element also forms a basic oxide and conducts as a solid, a Group 2 metal is plausible.

A single property is rarely unique. Use multiple independent clues and state what each one supports or rules out.