An atom consists of a positively charged nucleus orbited by electrons.

An atom consists of a very dense nucleus surrounded by a tenuous cloud of electrons.

Specifically, all atoms consist of electrons orbiting atomic nuclei ultimately constituted of up and down quarks.

It had been discovered that the atom consisted of a small, positively charged nucleus surrounded by a cloud of negatively charged electrons.

According to the Bohr model, an atom consists of a nucleus of protons and neutrons orbited by a number of electrons.

An atom, in the simplest model, consists of a nucleus and orbiting electrons.

This simple atom consists of a nucleus (containing the protons and neutrons) and an electron cloud.

The atom consists of protons and neutrons in the nucleus and electrons outside the nucleus.

In his plum pudding model, Thomson stated that an atom consisted of negative electrons randomly scattered within a sphere of positive charge.

Each atom consists of a cloud of negative charge (Electrons) bound to and surrounding a positive point charge at its center.