Introduction to Darmstadtium (Ds)
Darmstadtium (Ds) is a synthetic chemical element with the atomic number 110. It is an extremely heavy, radioactive element that does not occur naturally on Earth. Its name honors the city of Darmstadt, Germany, where it was first synthesized in 1994 by an international team of scientists at the Gesellschaft für Schwerionenforschung (GSI). Like other superheavy elements, Darmstadtium exists only for very short periods, making it challenging to study its chemical properties directly.
Atomic Structure of Darmstadtium
The atomic structure of Darmstadtium, like all elements, is defined by its number of protons, neutrons, and electrons. Since Darmstadtium is a synthetic element, its properties are primarily based on theoretical predictions and observations of very few atoms.
Protons
The atomic number of an element directly corresponds to the number of protons in the nucleus of each atom of that element. For Darmstadtium, with an atomic number of 110, there are 110 protons in its nucleus. The number of protons determines the element’s identity.
Neutrons
The number of neutrons in an atom varies among isotopes of an element. For Darmstadtium, several isotopes have been synthesized. One of the relatively longer-lived isotopes is Darmstadtium-281 ($^{281}$Ds). The number of neutrons can be calculated by subtracting the atomic number (Z) from the mass number (A).
For $^{281}$Ds: Neutrons = Mass Number (A) - Atomic Number (Z) Neutrons = 281 - 110 = 171 neutrons
It is important to note that other isotopes of Darmstadtium would have a different number of neutrons, but the number of protons would always remain 110.
Electrons
In a neutral atom, the number of electrons orbiting the nucleus is equal to the number of protons. Therefore, a neutral Darmstadtium atom possesses 110 electrons. These electrons are arranged in specific energy levels and orbitals around the nucleus.
Electron Configuration
The electron configuration describes the distribution of electrons in an atom’s atomic orbitals. For superheavy elements like Darmstadtium, relativistic effects significantly influence the electron configuration, making simple predictions less accurate. However, for high school chemistry, the configuration is typically derived by extending the Aufbau principle and Hund’s rule.
The abbreviated (noble gas core) electron configuration for Darmstadtium (Z=110) is predicted to be:
$[Rn] 5f^{14} 6d^8 7s^2$
Here:
- $[Rn]$ represents the electron configuration of Radon, the noble gas preceding Darmstadtium in the periodic table, accounting for the first 86 electrons.
- $5f^{14}$ indicates that the fourteen 5f orbitals are completely filled with 14 electrons.
- $6d^8$ indicates that the 6d subshell contains 8 electrons.
- $7s^2$ indicates that the 7s subshell is completely filled with 2 electrons.
Valence Electrons
Valence electrons are the electrons in the outermost shell of an atom, involved in chemical bonding. For transition metals, which include Darmstadtium (located in Group 10), the electrons in the outermost $s$ subshell and the partially filled $d$ subshell are generally considered valence electrons.
Based on the predicted electron configuration $[Rn] 5f^{14} 6d^8 7s^2$, the valence electrons are found in the $7s$ and $6d$ subshells.
Number of valence electrons = (electrons in $7s$ subshell) + (electrons in $6d$ subshell) Number of valence electrons = 2 + 8 = 10 valence electrons
This corresponds to Darmstadtium’s position as a Group 10 element in the periodic table.