Because it was difficult to analyze, Müller called it metallum problematicum (meaning “difficult metal”). Oxygen is a chemical element with atomic number 8 which means there are 8 protons and 8 electrons in the atomic structure. It is defined as being the charge that an atom would have if all bonds were ionic. This is, however, an average oxidation state for the two carbon atoms present. So the oxidation state of carbon must also be zero (rule 6). The silvery-white metal had the same density as antimony but very different properties. Element Oxygen (O), Group 16, Atomic Number 8, p-block, Mass 15.999. Hydrogen and oxygen have oxidation states of +1 and 2 (rules 4 and 5, respectively), resulting in a total charge for hydrogen and oxygen of (4 H atoms)(+1) + (2 O atoms)(2) 0. In writing the electron configuration for oxygen the first two electrons will go in the 1s orbital. Tellurium was discovered accidentally in 1782 by the Austrian chemist Franz Joseph Müller von Reichenstein, the chief surveyor of mines in Transylvania who was also responsible for the analysis of ore samples. Oxygen is the eighth element with a total of 8 electrons. Students can easily find S by using the atomic number of the noble gas that is one period above the element. It forms bonds with almost every other element and results in oxidation. In the equation S represents the number of inner electrons that screen the outer electrons. This sulfur deposit is located around a volcanic vent in Kilauea Crater, Hawaii. The equation for calculating the effective nuclear charge is shown below.

Elemental oxygen charge