Understanding the Atomic Structure of Tennessine (Ts)
Tennessine (Ts), with atomic number 117, is a synthetic, superheavy element located in Group 17 of the periodic table, placing it among the halogens. It is named after the U.S. state of Tennessee, a significant centre for superheavy element research. Due to its extreme instability and very short half-life (milliseconds for its most stable isotope), Tennessine has only been produced in laboratories, and its properties are largely predicted rather than experimentally observed.
Fundamental Particles in Tennessine
For a neutral atom of Tennessine, the count of protons and electrons is determined directly by its atomic number. The number of neutrons varies depending on the specific isotope.
Number of Protons
The atomic number of Tennessine is 117. Therefore, a Tennessine atom possesses 117 protons in its nucleus. The number of protons defines the element.
Number of Electrons
In a neutral atom, the number of electrons orbiting the nucleus is equal to the number of protons. Consequently, a neutral Tennessine atom has 117 electrons.
Number of Neutrons
Tennessine is a synthetic element, and several isotopes have been theorized or observed fleetingly. The most stable known isotope is Tennessine-294 ($^{294}$Ts), with a mass number of 294. The number of neutrons is calculated by subtracting the atomic number (number of protons) from the mass number: Number of neutrons = Mass number - Atomic number Number of neutrons = 294 - 117 = 177 neutrons It is important to note that other isotopes would have a different number of neutrons, but 294 is the mass number of the most commonly discussed and “stable” isotope.
Electron Configuration of Tennessine
The electron configuration describes the arrangement of electrons in the atomic orbitals of an atom. For Tennessine, with 117 electrons, the configuration follows the Aufbau principle, Hund’s rule, and the Pauli exclusion principle. Due to its high atomic number, a condensed notation using the noble gas preceding it is often used. The noble gas preceding Tennessine in the periodic table is Radon (Rn), which has an atomic number of 86.
The full electron configuration for a neutral Tennessine atom is: $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 4f^{14} 5s^2 5p^6 5d^{10} 5f^{14} 6s^2 6p^6 7s^2 6d^{10} 7p^5$
Using the noble gas notation, the configuration can be written more compactly as: $[Rn] 5f^{14} 6d^{10} 7s^2 7p^5$
Here, $[Rn]$ represents the electron configuration of Radon ($1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 4f^{14} 5s^2 5p^6 5d^{10} 6s^2 6p^6$). The subsequent electrons fill the $5f$, $6d$, $7s$, and $7p$ orbitals. The order reflects the increasing energy levels of the orbitals.
Valence Electrons in Tennessine
Valence electrons are the electrons located in the outermost shell of an atom, playing a crucial role in chemical bonding. For main group elements, these are typically the electrons in the highest principal quantum number ($n$) $s$ and $p$ subshells.
In the electron configuration of Tennessine ($[Rn] 5f^{14} 6d^{10} 7s^2 7p^5$), the highest principal quantum number is $n=7$. The electrons in the $7s$ subshell and the $7p$ subshell are considered the valence electrons.
- The $7s$ subshell contains 2 electrons.
- The $7p$ subshell contains 5 electrons.
Therefore, the total number of valence electrons in Tennessine is $2 + 5 = \textbf{7}$. This is consistent with its position in Group 17 (the halogen group) of the periodic table, where elements typically exhibit 7 valence electrons.