The first ionisation-energy values of an element are , ,

CHEMISTRY · Single correct · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties

Problem

The first ionisation-energy values of an element are

284

412

656

, and

3210\text{ kJ mol}^{-1}

. The number of valence electrons in the element is: (1) One (2) Two (3) Three (4) Four