The elements in Period 3 (Na through Ar) display a regular change in…
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
The elements in Period 3 (Na through Ar) display a regular change in electronegativity values that chemists have correlated with their electronic structures.
Use the information in the periodic table excerpt below. (Atomic numbers are given in parentheses.)
Na (11) Mg (12) Al (13) Si (14) P (15) S (16) Cl (17) Ar (18)
Respond to each of the following prompts.
(a) Describe qualitatively how the electronegativity of these eight elements changes from Na to Cl.
(b) Explain the trend you identified in part (a) in terms of both (i) effective nuclear charge and (ii) the principal quantum number of the valence electrons.
(c) Argon is not assigned an electronegativity value on the Pauling scale. Propose a reason for the omission that is consistent with your explanation in part (b).