Railway Science (Chemistry-Metals , Non-Metals and Alloys)

It is an allotrope of carbon. Under high pressures and temperatures, graphite converts to diamond. Bromine (Br, 35) - The only non-metal which is liquid at room temperature. Phosphorus (P, 15) - A multivalent non-metal of the nitrogen group. Hydrogen (H, 1) - The lightest element in the periodic table.

Alkali metals (s-block elements) : Alkali metals are highly reactive when compared to remaining metals because they have only a single electron in their outermost shell and can easily lose it due to their large size and less nuclear attraction force.
Alkali elements : Lithium (Li, 3), Sodium (Na, 11), Potassium (K, 19), Rubidium (Rb, 37), Cesium (Cs, 55) and Francium (Fr, 87). Hydrogen (H, 1) : The lightest element in the periodic table. It varies greatly from the alkali metals as it forms cations (H+ ) more reluctantly than the other alkali metals.

It is used to treat Goitre. The body needs iodine to make thyroid hormones. Iodine is a nonmetal which is lustrous. Its Atomic number (53) belongs to the Halogen group. Some halogens and their state at room temperature: Solid- Iodine, Astatine; Liquid- Bromine; Gas- Fluorine, Chlorine.

In the periodic table the elements which are in diagonal relationship with Beryllium (Be) are Magnesium (Mg) and Aluminum (Al). Not only shining other properties like color, hardness, reaction with water and reaction with oxygen are also the same. Some other elements : Lithium (Li, Atomic number - 3), Radon (Rn, Atomic number - 86), Zinc (Zn, Atomic Number - 30).

Mn, Atomic number-25). Trace element (Microminerals) - Elements whose concentration is lower than thousand (1000) parts per million or 0.1 % of the original or parent rock composition. Examples : Copper, Cobalt, Iodine, Zinc, mercury, lead.

Valence electrons: The electrons present in the outermost shell of an atom. An outermost-shell, which had eight electrons was said to possess an octet. Valency - The number of electrons gained, lost or shared so as to make the octet of electrons in the outermost shell, gives directly the combining capacity of the element. Aluminum (Al) - 3 valence electrons. Silicon (Si) - 4 valence electrons. Sodium (Na) - 1 valence electron.

Atomicity - Number of atoms present in a molecule of elements. It can be Monatomic elements (single atom) - Helium (He), Neon (Ne), Argon (Ar), Xenon (Xe). Diatomic elements (Two atoms of same element) - Hydrogen (H₂), Oxygen (O₂), Fluorine (F₂), Chlorine (Cl₂). Polyatomic elements (More than 2 atoms bonded by covalent bond) - Selenium (Se), Sulphur (S) and Phosphorus (P).

Ionization energy: The amount of energy required to remove an electron from an isolated atom or molecule.Nitrogen has higher ionization energy than Oxygen because it has a stable half-filled electronic configuration . 7 N - (1s)² (2s)² (2px)¹ (2py)¹ (2pz) and 8 O - (1s)² (2s)² (2px)² (2py)¹ (2pz)¹ .

It is a single-atomic-layer of carbon atoms arranged in a hexagonal lattice. Fullerene is an allotrope of carbon wherein its molecules consist of carbon atoms that are connected by single and double bonds.
Silicon is the most abundant electropositive element in Earth's crust. It's a metalloid with a marked metallic luster and very brittle. Quartz is a hard, crystalline mineral composed of silica (Silicon dioxide).

It is a soft, silvery-white, metal that heads group 1, the alkali metals group, of the periodic table of the elements. It reacts vigorously with water. It is the lightest metal, with a density about half that of water. It is the least dense solid element. A highly reactive and inflammable element. The size of the atoms of an element increases as we go down the group. The atomic size tends to decrease across a period from left to right.