For elements composed of single atoms, which statement is true?

For elements composed of single atoms, it is accurate that the number of protons equals the number of electrons. This relationship is fundamental to the nature of an atom.

In a neutral atom, the overall charge must be balanced, which means the number of positively charged protons in the nucleus is equal to the number of negatively charged electrons surrounding the nucleus. This balance results in a neutral charge, which is the common state for most elements under typical conditions.

When discussing atomic structure, it is important to note that the number of neutrons can vary within the same element, resulting in different isotopes, but this does not affect the equal number of protons and electrons in a neutral atom.

Thus, the statement correctly reflects this critical principle in atomic theory.