Yes, there is matter present between two orbitals of atoms. In the quantum mechanical description of atoms, electrons are not strictly confined to specific orbits like planets around the sun. Instead, they occupy regions of space called orbitals, which are probability distributions that describe the likelihood of finding an electron in a particular location.
The shape and size of an orbital are determined by the energy of the electron and the forces acting on it. Different orbitals have different shapes, such as spherical, dumbbell-shaped, or more complex patterns. These orbitals are labeled by quantum numbers such as n, l, and m, which specify their energy, shape, and orientation.
Between two neighboring orbitals, there is a finite probability of finding an electron. This means that there is a non-zero electron density in the space between the orbitals. The electron density represents the probability of finding an electron at a given point in space. While the electron density may be lower in regions between orbitals compared to within the orbitals themselves, there is still a presence of matter in those regions.
It's important to note that the concept of orbitals and electron density is a result of the quantum mechanical description of atoms and the behavior of electrons. In classical terms, we might think of atoms as consisting of discrete particles moving in well-defined orbits, but in reality, the behavior of electrons is governed by the laws of quantum mechanics, which describe the electron's wave-like nature and its distribution in space.