Explain the size of atomic radii observed in the periodic table

The size of atomic radius increases down the group but decreases from left to right across the period. Atomic radius is defined by the distance of protons in nucleus to surrounding electron shells. Mainly, two factors influence the size of the atomic radius: (a) atomic number and (b) shielding. First, increasing atomic number suggests a smaller atom due to higher number of protons in its nucleus. The higher density of protons increases the positive nucleus charge and allows to attract electrons more efficiently. Secondly, phenomena known as shielding increases the atomic radius due to electrons repulsing each other. Electrons that are closer to the nucleus will repulse the outermost ones due to possessed negative charges, therefore increasing the average distance from nucleus to electrons.

Answered by Viktoras S. Chemistry tutor

1479 Views

See similar Chemistry IB tutors

Related Chemistry IB answers

All answers ▸

What is the limiting reagent and thus the mass of product for the reaction: P4O10 + 6H2O --> 4H3PO4 if 5.00 g of P4O10 react with 1.50 g of water?


In the addition of hydrogen bromide to propene, consider which of the two possible products, 1-bromopropane and 2-bromopropane, will be the major product and why.


Why is there a significant difference between the radii of first and second row transition metals, where as no difference (or even a decrease) is observed between the second and third rows?


Explain why Sc3+(aq) is colourless, while Ni2+(aq) is green.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences