A Level Chemistry OCR Practice Exam

Which of the following is true about atomic orbitals?

1. They can hold more than two electrons

2. They always form spherical shapes

3. They exhibit electron density distribution

4. They determine the chemical reactivity of an element

The correct answer is: They exhibit electron density distribution

The correct answer is that atomic orbitals exhibit electron density distribution, which means they describe the probability of finding an electron in a particular region of space around the nucleus of an atom. This concept is integral to quantum mechanics and illustrates that electrons do not occupy fixed positions but rather exist in areas where they are most likely to be found. The shapes and sizes of the orbitals reflect how likely it is to find an electron in various locations, contributing significantly to our understanding of chemical bonding and molecular geometry. Other options provide insights about atomic orbitals but do not accurately reflect their fundamental properties. For example, while atomic orbitals can be more complex than simply holding two electrons, the basic guideline is that each orbital can accommodate a maximum of two electrons, aligned with the Pauli exclusion principle. Not all orbitals take on spherical shapes; some have distinct geometries, like p orbitals, which are dumbbell-shaped. Lastly, while orbitals do influence an element's chemical reactivity by determining the distribution and energy of electrons, they serve as a framework for understanding electron arrangements rather than being the sole determinants of reactivity.