Define atomic size. How does it vary along the group
and along the period?
Answers
Answer:
atomic size is the distance from nucleus to the valence shell of the atom.
It decreases from left to right across a period and increases down the group.
Answer:
Atomic size is the distance between the centre of the nucleus of an atom and its outermost shell and the atomic radius is defined as theshortest distance between the atom’s nuclei and the outermost shell of the atom.
Explanation:
Explanation:
Atomic size decreases across a Period from left to right as we face the Table, but INCREASES down a Group, a column of the Periodic Table. This is one of the most fundamental and useful ideas you can learn as you are introduced to chemistry
Atomic size is influenced by (i) nuclear charge,
Z
, and by (ii) shielding by other electrons. Incomplete electronic shells shield nuclear charge VERY ineffectively. The result? As we add electrons to the same valence shell, we also add protons to the nuclear charge. And thus across the Period
nucular charge
predominates, and draws the valence electrons towards the nuclear core, with the result of a marked decrease in atomic radius. Is this evident in the diagram?
Once a valence shell is filled, the nuclear charge is shielded with reasonable effect. A new quantum shell is initiated, farther from the nuclear core, with the Periodic pattern again repeated across the new Period.
I urge you to read your text in this respect. This contest between nuclear charge,
Z
, and shielding by other electrons, underlies the pattern of the Periodic Table, and the electronic structure of course determines the reactivity of each element. Capisce?