Explain the variation of atomic radius along a period and along a group of the Periodic Table

The atomic radius is mostly influenced by the electron cloud and its interaction with the nucleus.Along a period, the atomic number increases, which indicates that the number of electrons also increases, given that an atom is a neutral species. However, the added electrons remain in the same orbital. At the same time, the number of protons increases, increasing the nucleus-electron cloud attraction. This overpowers the increment in electrons, so the atomic radius decreases.Along a group, however, the electrons are added to a new, more peripheral orbital. As such, this growth in volume is not compensated by the nucleus-electron cloud attraction, even though the number of protons is increasing. Thus, the radius increases.

MC
Answered by Madalena C. Chemistry tutor

2655 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

Use the following data to explain why NaCl is soluble in water: ∆H = +31 kJmol-1, S(Na+(aq)) = 320.9 JK-1mol-1, S(Cl-(aq)) = 56.5 JK-1mol-1, S(NaCl(s)) = 72.1 JK-1mol-1 Are there any temperatures at which you would not expect NaCl to dissolve?


What is the difference between benzene and cyclohexene?


In terms of Electrostatic Forces, Suggest why the ‘Electron Affinity’ of Fluorine has a Negative value.


Define a transition metal


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning