Classes of metals Classes of metals Class A metals are metals that form hard acids. Hard acids are acids with relatively ionic bonds. These metals, such as iron, aluminium, titanium, sodium, calcium and the lanthanides, would rather bond with fluorine than iodine. They form stable products with hard bases, which are bases with ionic bonds. They target molecules such as phospholipids, nucleic acids and ATP. Class B metals are metals that form soft acids. Soft acids are acids with relatively covalent bonds. These metals, such as lead, gold, palladium, platinum, mercury and rhodium, would rather bond with iodine than fluorine. They form stable
Period 5 element years old, helped bolster the theory that stars can produce heavier elements. Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most chemicals. The Russian scientist Karl Ernst Claus discovered the element in 1844 and named it after Ruthenia, the Latin word for Rus'. Ruthenium usually occurs as a minor component of platinum ores and its annual production is only about 12 tonnes worldwide. Most ruthenium is used for wear-resistant