International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

Which statement is true regarding electrons in an atom?

1. Electrons have a mass equivalent to protons

2. Electrons are located in the nucleus

3. Electrons are involved in chemical bonding

4. Electrons have a positive charge

The correct answer is: Electrons are involved in chemical bonding

The statement that electrons are involved in chemical bonding is correct because electrons play a crucial role in the interactions between atoms that lead to the formation of molecules. Chemical bonding primarily revolves around the sharing or transferring of electrons between atoms. In covalent bonds, for example, atoms share one or more pairs of electrons, while in ionic bonds, electrons are transferred from one atom to another, resulting in the formation of charged ions that attract each other. Understanding the role of electrons in bonding is fundamental to grasping concepts in chemistry, as it explains how molecules are formed and how different substances interact with each other. This knowledge is foundational for topics such as reactivity, molecular structures, and the properties of materials based on their electron configurations. The other options provide incorrect information about electrons. Electrons have a significantly smaller mass than protons and are not located in the nucleus but rather occupy regions of space around the nucleus known as electron shells or orbitals. Additionally, electrons carry a negative charge, not a positive one. This understanding of electrons is key to the study of atomic structure and chemical reactions.