Nimo

Study smarter with Nimo

Personalised revision that adapts to you. Ace your revision with unlimited practice questions that are designed to help you learn faster. We're slowly rolling out to more and more students.

Try Nimo

Periodicity and atomic structure overview

Key ideas • General

Key concepts

What you'll likely be quizzed about

  • Periodicity describes the repeating pattern of chemical and physical properties of elements ordered by increasing proton number.
  • Similar properties recur at regular intervals because of repeating electron configurations across periods.
  • Limitations arise from sub-level filling and the behavior of transition metals, which can cause deviations from straightforward patterns.

Flashcards

Test your knowledge with interactive flashcards

What role does shielding play in periodic trends?

Click to reveal answer

Shielding from inner electrons decreases the effective nuclear attraction on outer electrons, leading to larger atomic radii and lower ionisation energy.

Key notes

Important points to keep in mind

Periodicity results from repeating electron configurations when elements are ordered by proton number.

Atomic radius decreases left to right across a period due to increasing nuclear charge with similar shielding.

Atomic radius increases down a group because electrons occupy higher principal energy levels and shielding increases.

First ionisation energy generally rises across a period and falls down a group due to nuclear charge and shielding effects.

Electronegativity generally increases across a period and decreases down a group.

Subshell filling, electron pairing, and d-block electrons cause exceptions to simple periodic trends.

Effective nuclear charge predicts many periodic trends, computed as nuclear charge minus shielding.

Metallic character is related to ease of losing electrons: decreases across a period, increases down a group.

Built with v0