Yes, it is true that atoms never truly "touch" each other in the classical sense. Atoms are the basic building blocks of matter and consist of a nucleus, containing protons and neutrons, surrounded by a cloud of electrons. When two objects come into contact, it may appear as though the atoms are touching, but at the atomic scale, there are forces at play that prevent true contact.
The reason for this is primarily due to the nature of the electromagnetic force, which governs the interactions between charged particles like electrons. Electrons have a negative charge, and like charges repel each other. As two objects approach each other, the electrons in their respective atoms begin to interact. The repulsive force between the negatively charged electrons prevents the atoms from getting too close to each other.
Instead of direct physical contact, what we perceive as "touch" is actually the result of electromagnetic forces at work. When you press your hand against a solid object, for example, the electrons in the atoms of your hand and the object repel each other, creating a sensation of resistance. This repulsion is what we interpret as the sensation of touch.
It's important to note that at extremely small scales, such as in quantum physics, the concept of "touch" becomes even more complex. Quantum mechanics introduces concepts like electron cloud density and quantum tunneling, which further illustrate that direct physical contact at the atomic level is not a straightforward concept.
So while objects may seem to touch in everyday life, at the atomic scale, there is always a tiny gap due to the repulsive electromagnetic forces between the electrons of the atoms involved.