Element Barium, Ba, Alkaline Earth Metal. Has the combining weight 137. 4, and occurs naturally as sulphate and carbonate. Metallic barium is of a white colour, melts at a red heat, and reacts more energetically with water than strontium or calcium. We have here, therefore, a repetition of the same state of affairs as in the group of alkali metals, viz. the action with oxygen and oxygen compounds is more energetic the higher the combining weight of the metal. Barium forms only the divalent ion Ba.

Element Calcium, Ca, Alkaline Earth Metal. The element also takes part in the most varied way in the building up of the organisms. Calcium has also been found in meteorites, and by spectral analysis in the sun and fixed stars.

Element Rubidium, Rb, Alkali Metal. During their investigations they became interested in the mineral lepidolite. The processed 150 kg and, as a result, separated double potassium, caesium and rubidium. The crustal abundance of rubidium.

Element Samarium, Sm, Lanthanide. Samarium is one of the less common of the rare earth elements, being on the one hand much less abundant than the other elements of the cerium group, and on the other hand much more abundant than europium, terbium, and thulium. It is about as plentiful as gadolinium. Samarium is a yellow metal of density 7. The metal quickly tarnishes in the air. Extracted by Mosander from ceria earth. The samarskite mineral was named.

Element Lanthanum, La, Lanthanide. Lanthanum is a tin-white metal of density 6. It is malleable, but not ductile. Measurements made with material of doubtful purity indicate that lanthanum is feebly paramagnetic, but this is questionable. 923 and its heat of formation 97. it resembles the corresponding cerium compound.

Element Potassium K, Alkali Metal. While the knowledge of some of the potassium. After it had been obtained in this way, the method of preparing it by purely chemical means was soon discovered, a method which was for long the only one employed. The most important of these reactions is the heating of potassium carbonate with charcoal; carbon monoxide and metallic potassium. Are formed, the latter of which volatilises and is condensed under rock oil - K. It is a constituent of the waters of.

Element Caesium, Cs, Alkali Metal. Had undoubtedly been examined before, but had been mistaken by C. Plattner for potassium salts, meanwhile it was consisting of hydrous caesium. Pisani revealed it on the analysis of pollux in 1864.

Element Yttrium, Y, Transition Metal. As an element of the 3. Group in periodic system, does not belong to the group rare earth metals; however the history of its discovery is closely connected with rare earth elements. A lustrous black color mineral. Ekeberg extracted an earth from this mineral and named it yttria. 45 years later Mosander extracted yttrium.