Q.Explain the following:
Alkaline earth metals have low values of electronegativity; which decrease down the group.

Step 1. Why electronegativity is low overall. Electronegativity measures an atom's tendency to attract a shared pair of electrons in a bond. Alkaline earth metals are strongly electropositive — they would rather lose their two ns² electrons entirely (to form M²⁺) than attract more electron density — so their electronegativity values are low across the whole group (roughly 1.5 down to 0.9, per Table 8.5).

Step 2. Why electronegativity falls further down the group. Going down the group, each successive element has one more occupied shell, so its valence electrons sit farther from the nucleus and are increasingly shielded by inner-shell electrons. A farther, more shielded outer shell is held less tightly, and so attracts a shared electron pair even less strongly — hence electronegativity decreases from Be (1.5) to Ba (0.9).

Relating electronegativity trend to atomic size and shielding down group 2

• Confusing electronegativity with ionization enthalpy — they trend the same way down the group but measure different things (attracting a shared pair vs removing an electron entirely).
• Forgetting that beryllium, being anomalously small, has a noticeably higher electronegativity than the rest of group 2, consistent with its more covalent chemistry (section 8.2.5).