The following 3D models of atoms are initial designs. Since several forces act on each nucleon, their exact configuration depends on the performance of computer computational simulations. The above suggestions should therefore be considered as a starting point for further optimization. Atom nuclei cannot be considered static. Distances between nucleons are stretched and shortened as possible, nucleons tilt, twist and, if the configuration allows, even rotate. These are manifestations of the thermal energy of the atom and, among other things, have an effect on the melting temperature. The location of the electrons is also symbolic, because they oscillate in the radial direction around their equilibrium state and this can change significantly depending on the surrounding conditions. Especially compared to the bond angles of chemical bonds such as in CH4 can be misleading because these angles are often a kind of average of different positions, as will be shown in a specific case later. On the other hand, the bond angles of double bonds provide an interesting comparison with reality. The basic atom configuration should be considered as a certain equilibrium state.
They are shown with larger gaps between nucleons than will correspond to reality. I believe that this will serve to better study the model.
Hydrogen
Hydrogen is the simplest element. An atom contains only a proton and an electron. It can be found in the literature that its covalent radius is approx. 31 pm Van der Waals radius is approx. 120 pm. According to the theory described above, it can be assumed that the first value represents the equilibrium distance of the electron and the second its maximum oscillation distance under normal conditions. It is probably the only atom where an electron can truly orbit around the atomic nucleus without restriction. The way hydrogen crystallizes confirms that its radial and axial sides are different. So the assumption of planarity of the atom. The atom itself, or the cation created from it, i.e. the proton, creates the impression of a sphere by rotating its angular momentum axis in the space.
Deuterium
Deuterium is stable isotope of hydrogen that contains an extra neutron in its nucleus. According to the above theory, this atom should have a higher covalent radius and also a lower electronegativity. On the other hand, it can be assumed that the proton and neutron orbit each other, which reduces the effect of the neutron on the proton. Even in this case, the electron can orbit the nucleus, but its movement is also controlled by the neutron orbiting the proton.
Tritium
Tritium is a radioactive isotope of hydrogen with a half-life of 12.3 years. The decay product is 3He (https://en.wikipedia.org/wiki/Tritium). Tritium contains one proton and two electrons in its nucleus. This arrangement proves that one proton is able to keep two neutrons in a pair for a long time. The attractive force between neutrons is much weaker than the attractive force between neutrons and proton. It can be assumed that due to the movement of the atom, the distance between the two neutrons will be variable. The neutrons will move away from each other and bump into each other. The 3D model is depicted in the next figure.
3D model of 3H atom
Helium 3He
Helium 3He is a minor but stable isotope of Helium. It is created, among other things, by the decay of tritium (https://en.wikipedia.org/wiki/Helium-3). This arrangement proves that one neutron is able to keep two protons in a pair. Although, as in the case of tritium, the bond between the protons is much weaker than the bond between the protons and the neutron, in this case the two electrons play the role of an additional bond, which strengthens the bond between the two protons. The 3D model is depicted in the next figure.
3D model of 3He atom
Helium 4He
Helium 4He is probably the largest stable 2D atom. It contains two protons and two neutrons in the nucleus. https://en.wikipedia.org/wiki/Helium#/media/File:Helium_atom_QM.svg
In this configuration, it contains a total of four very strong neutron-proton interactions and two weaker neutron-neutron and proton-proton cross interactions. This arrangement guarantees a very high strength of the core. Considering this fact, it is likely that the pulsation of individual particles will be strongly limited and the electrons will be located close to the nucleus. Which is consistent with the reported covalent radius of 28 pm. Although the elements 3He and 4He are considered to be isotopes of the same element, they are actually completely different substances. So much so that their liquefied forms are immiscible. This is caused by a completely different arrangement of electrons in atoms, as can be seen from the following picture. Because of this, it is likely that 3He, unlike 4He, will tend to form 3He2 molecules like most gases. The 3D model is depicted in the next figure.
3D model of 4He atom