Periodic Properties and Variations of Properties - Physical and Chemical

Ionization energy, Electronegativity, Non-metallic character

Across a period, nuclear charge increases while electron shells remain same, leading to increased attraction for electrons. This increases ionization energy, electronegativity, and non-metallic character.

1

All alkali metals (Group 1 elements) have one electron in their outermost shell, which they readily lose to form +1 ions.

It is the energy released when an electron is added to a gaseous atom, Halogens have high electron affinity values, It generally increases across a period

Electron affinity is energy released during electron addition. Halogens readily accept electrons to complete their octet. Noble gases have stable configurations so low electron affinity.

Magnesium has higher nuclear charge

Both Na and Mg have the same number of electron shells, but Mg has higher nuclear charge (+12) compared to Na (+11), pulling electrons more strongly and reducing atomic size.