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

Alkali metals (Group 1) are known to react violently and explosively with water. This is because enough heat is given off during the exothermic reaction to ignite the H₂(g). Metals such as Sodium, Potassium react violently with cold water. The reaction is so violent and exothermic that the evolved hydrogen immediately catches fire.

The melting point is the temperature at which a substance changes state from solid to liquid at atmospheric pressure. Latent heat of fusion - Amount of heat required to melt a unit mass of a solid at its melting point.
Boiling point - The temperature at which a liquid boils and changes into a gas at atmospheric pressure. Latent heat - The heat released or absorbed by a substance during a change of state, such as melting or boiling.

These electrons act as charge carriers in the metallic structure, allowing electric current to flow through them. Conductor allows current to flow easily through it. Silver, Copper, and Aluminum are examples of good conductors of heat and electricity. Insulators - It doesn't allow current to flow through them. They are non-conductive because they do not possess any free charge carriers. Examples: Glass, Wood, Plastic.

It represents a non-metal because it ends with 5 electrons in the outermost shell. The non-metals and metalloids exist only in the p-block of the periodic table.

2,8,4 is the electronic configuration of Silicon (Si). Silicon is a metalloid (neither metal nor nonmetal). It is the second most abundant element in the Earth's crust after oxygen. 2, 8, 7 is the electronic configuration of Chlorine (Atomic number= 17, and Non-metal from the Halogen family). 2, 8, 6 is the electronic configuration of Sulfur (Atomic number= 16, and Non-metal). 2, 8, 5 is the electronic configuration of Phosphorus (Atomic number= 15, and Non-metal).

The element with the electronic configuration (2, 8, 3) is Aluminum as it has the atomic number 13 and symbol Al. The electronic configuration of an element describes how electrons are distributed in its atomic orbitals. Electronic Configuration of the element (2, 8, 6) - Sulphur (Non-metal). Electronic Configuration (2,8,4) - Silicon (Non-metal). Electronic Configuration (2,8,5) - Phosphorus (Non-metal).

Properties - Soft Metal, Highly Reactive, Good Conductor, Low Density, 6th most abundant element on the Earth. Location - first Group. Melting and Boiling Points of other elements - Iron (Fe) - High, Copper (Cu) - high but Lower than Iron, Gold (Au) - Low melting point and High Boiling Point.

Non-metals: These generally have 5 to 7 electrons in their valence shell and tend to form covalent bonds with other atoms. Halogens : This specific group within the non - metals typically has 7 electrons in their valence shell. Metalloids: These elements exhibit properties intermediate between metals and non-metals, having varying numbers of valence electrons (4 or 5).

It belongs to Group 2 (IIA) in the periodic table. It has two electrons in its outermost valence shell and tends to lose two electrons to form cations. Therefore, it is classified as an alkaline earth metal. Alkali metals: These belong to Group 1 (IA) in the periodic table. Examples include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

Brass is a metal alloy and used in pipes and tubing, musical instruments, and decorative items. Important Alloys: Bronze = Cu + Sn; German Silver = Cu + Zn + Ni; Rolled Gold = Cu + Al; Solder = Pb + Sn; Stainless steel = Fe + Cr + Ni + C.