A Level Chemistry OCR Practice Exam

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Prepare effectively for the A Level Chemistry OCR Exam with our valuable resources, including multiple choice questions and hints. Unlock your potential and ace your exam with comprehensive practice materials designed for your success!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What is a lone pair of electrons?

An outer-shell pair of electrons involved in bonding
An inner-shell pair of electrons with no charge
An outer-shell pair of electrons not involved in bonding
A pair of electrons that are free to move

The correct answer is: An outer-shell pair of electrons not involved in bonding

A lone pair of electrons refers to two electrons that are located in the outermost shell of an atom but are not engaged in chemical bonding with other atoms. These electrons are significant because they influence the geometry and reactivity of molecules. Lone pairs occupy space around the atom and can affect the overall structure by causing repulsion between other electron pairs, leading to various molecular shapes and angles. In contrast, options that describe electrons involved in bonding or free to move do not accurately define what a lone pair is. Lone pairs play a crucial role in understanding molecular geometry and the behavior of compounds, making option C the correct description.