Galileum

**Galileum** is the provisional non-systematic name of the discovered element **unbinilium** with the symbol **Gl** and atomic number **120**. Galileum was named in honor of *Galileo Galilei* (1564–1642), father of modern science who discovered four largest moons around Jupiter using the newly invented telescope, proving that other planets have moons; he also made few other astronomical discoveries such as sunspots and craters on the Moon. Galileum is known in scientific literature with its provisional name, *unbinilium* (*Ubn*), or sometimes as **eka-radium** or simply **element 120**. Galileum is the seventh alkaline earth metal and located in the periodic table coordinate 8s2.

Galileum's position as the seventh alkaline earth metal makes it properties similar to its lighter congeners; however, relativistic effects may cause some of its properties to differ from those expected from a straight application of periodic trends. For example, galileum is expected to be less reactive than barium and radium and be closer in behavior to strontium, and while it should show the characteristic +2 oxidation state of the alkaline earth metals, it also shows the +4 and +6 oxidation states, which are unknown in any other alkaline earth metal.

## History

Elements 114 to 118 (flerovium through oganesson) were discovered in "hot fusion" reactions bombarding the actinides plutonium through californium with calcium-48, a quasi-stable neutron-rich isotope which could be used as a projectile to produce more neutron-rich isotopes of superheavy elements. This couldn't easily be continued to elements 119 (newtonium) and 120 (unbinilium, later galileum), because it would require a target of the next actinides einsteinium and fermium. Tens of milligrams of these would be needed to create such targets, but only micrograms of einsteinium and picograms of fermium have so far been produced. More practical production of further superheavy elements would require projectiles heavier than 48Ca, but this is expected to be more difficult. Attempts to synthesize newtonium and unbinilium pushed the limits of current technology in the first decade of the 21st CE, due to the decreasing cross sections of the production reactions and their probably short half-lives, expected to be on the order of microseconds. However, in 2021, this element was found near the Southern Ocean, near an old Oganesson Bomb Test at the Gauntlet Archipelago.

## Properties

### a. Atomic Properties

Galileum contains 120 electrons in the cloud of 8 shells and 20 orbitals, both are factors of 120, resulting in the electron notation 120-8-20. Electrons surround the tiny nucleus compared to its atomic size, but contains almost all of the atom's mass. The nucleus has a nuclear ratio of 1.67, as it is comprised of 200 neutrons and 120 protons.

#### Isotopes

Like every other trans-lead element, Galileum has no stable isotopes. The most stable isotope is 320Gl with a half-life as long as 322 million years, alpha decaying to 316Og. All other isotopes have half-lives less than 8 months. 326Gl is another interesting isotope that has a half-life of 4.45 days, beta decaying to 326Ls. Galileum, like every other trans-calcium element, has meta states, which are excited states of isotopes. The longest-lived meta state is 313mGl with a half-life of 2.3 days and decays to neutron-deficient isotope 313Gl by emitting gamma rays as well as alpha particles. The second longest-lived meta state is 323mGl whose half-life is close to 313mGl at 1.7 days. 323mGl decays to 323Gl through isomeric transition.

### b. Chemical Properties

Galileum has chemical properties similar to strontium and barium. Like all other alkaline earth metal elements, galileum exhibits a strong +2 oxidation state (divalent), meaning it can give up both electrons in its filled outermost orbital when combining with other element and formation of ions of same value when dissolved in water forming colorless solution like all other alkaline earth metals such as magnesium and calcium. However, due to shorter separation between outermost shell and the next shell further in, galileum is also the first alkali metal to exhibit a +4 oxidation state (tetravalent), meaning it can give up two 8s electrons and two 7p1/2 electrons. Galileum would quickly tarnish in the air to form an oxide and readily react with water to form a hydroxide.

### c. Physical Properties

Galileum, like most other metals, is a gray metal. Its density is 6.9 g/cm3, the densest of any other alkaline earth metal. Its high density for an s-block element is due to its high atomic mass. The molar mass of 322.7 g is directly derived from its atomic mass. Its molar volume is calculated by dividing molar mass by density. For galileum, this results in the molar volume of 46.8 cm3, when compared to other members, one mole of galileum takes up the most space. Based on its molar mass and density, one cubic centimeter of galileum contains 12.9 sextillion atoms, a bit more than estimated number of stars in the observable universe. Atoms that form body-centered cubic lattice are separated by 4.27 Å apart on average. Sound travels at 1029 m/s through thin rod of metal via vibrations. Like all other alkaline earth metals, galileum is attracted by externally applied magnetic field, so this metal is paramagnetic.

As expected from periodic trend, galileum has a lower melting but boiling points go up and down. Galileum has a melting point of 956 K (683 °C), compared to 973 K (700°C) for radium and 1000 K (727°C) for barium. Its boiling point is 1968 K (1695°C), compared to 1413 K (1140 °C) for radium and 2170 K (1897°C) for barium. Galileum requires less energy to melt. This a hypothetical element with higher atomic number than any of the lighter members of the group, but the amount of energy required to boil it is the second highest. Also galileum has the third widest liquid range of any alkaline earth metals at 1012 K, which is the difference between melting and boiling points, as well as the second highest liquid ratio at 2.06, which is the boiling point per melting point ratio. However, the phase points are not the same at every pressure, as phase points mentioned are based on Earth's sea level pressure of 101.325 kPa (101325 Pa, 0.101325 MPa). Pressure has far more effect on boiling point than melting point, because boiling point is determined by its vapor pressure. Boiling point, one of two variables for liquid range and ratio, is directly proportional to ambient pressure. Lowering the ambient pressure enough would converge melting point and boiling point. As a result, at converged phase points, all three states are stable as solid, liquid, or gas at precisely 956.38 K (683.23°C), and at a pressure of 417.28 pascals. On the phase diagram, this point is called its triple point, termed because triple means three, as all three states are stable at that point. Whereas if we raise the pressure, we'll be going to the point opposite of triple point on the phase diagram, called the critical point. For galileum, it is 2844 K (2571 °C) under a pressure of 107 MPa. When heated or pressurized beyond this point, the substance would exist as a supercritical fluid, which has properties of both liquid and gas, and as a result blurs the distinction between these two states.

## Occurence

This hypothetical element can also be produced artificially in much larger quantities by advanced technological civilizations, making artificial galileum more abundant than natural galileum in the universe. An estimated abundance of galileum in the universe by mass is 2.78 × 10−24, which amounts to 9.29×1028 kg or about 49 Jupiters worth of galileum in mass. Also, this element was found in the ocean, near an old oganesson bomb test.