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Pairs of outermost shell electrons that are not used in bonding are called lone pairs or non-bonding pairs. A lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bond and is sometimes called an unshared pair or non-bonding pair. Lone pairs are found in the outermost electron shell of atoms.

Isoelectronic species are atoms, ions, or molecules that have the same number of electrons and therefore, the same electronic configuration, even if they are different elements. For \(_8\)X\(^{2-}\) Number of protons = 8, while Number of electrons = 10, because X gains 2 electrons and outnumbers the number of protons. Also, for \(_{10}\)Y, Number of protons = 10, while Number of electrons = 10, because Y has no charge, it is a neutral atom. Hence, the number of protons = Number of electrons =10 Since the number of electrons are the same in both atoms of element X and element Y, even though they are of different elements, they are said to be isoelectronic species. Therefore, \(_8\)X\(^{2-}\) and \(_{10}\)Y are Isoelectronic

Pure water contaminated with quicklime (calcium oxide) will have a highly alkaline pH, significantly above 7. The reason being that quicklime (CaO) reacts vigorously with water to form slaked lime (calcium hydroxide, Ca(OH)₂), a strong base.

The electron configuration of copper (Cu), with atomic number 29, is [Ar] 3d¹⁰ 4s¹ or 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹. Here's a more detailed explanation: Atomic Number:Copper (Cu) has 29 electrons. Following the Aufbau principle, the expected configuration would be 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁹. However, copper exhibits an exception to this rule. A full or half-filled d-orbital is more stable than a partially filled one. Therefore, one electron moves from the 4s orbital to the 3d orbital, resulting in the configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹ or [Ar] 3d¹⁰ 4s¹.

When s and p block elements react, the bond formed is typically ionic or electrovalent, as s-block elements tend to lose electrons to achieve a stable electron configuration, while p-block elements, especially nonmetals, readily gain electrons. These elements(alkali and alkaline earth metals) have low electronegativity and readily lose electrons to form positively charged ions (cations). On the other hand,the P-block elements, especially non-metals like halogens and oxygen, have high electronegativity and readily gain electrons to form negatively charged ions (anions). The electrostatic attraction between these oppositely charged ions results in the formation of an ionic bond or electrovalent bond.

Diamond is the hardest form of carbon. It's also the hardest naturally occurring substance on Earth. Diamond is an allotrope of carbon, meaning it's a variation of carbon's structure. In diamond, carbon atoms are arranged in a tetrahedral structure, with each carbon atom bonded to four other carbon atoms. This structure creates a rigid, three-dimensional network of carbon atoms. Thus,the strong bonds between the carbon atoms make diamond extremely hard.

The strong metallic bonding in aluminum is due to a large number of delocalized electrons that are shared among the metal atoms, creating a "sea" of electrons that strongly attracts the positively charged metal ions. In metallic bonding, the outermost electrons of metal atoms are not bound to any specific atom but are free to move throughout the entire structure. These electrons form a "sea" or "cloud" of negative charge. The positively charged metal ions (cations) are attracted to this "sea" of delocalized electrons, creating a strong electrostatic attraction that holds the metal atoms together.

Nitrogen typically forms three covalent bonds. However, it can form four or five bonds in some cases. Explanation Nitrogen has five valence electrons. To fill its outer shell, it needs three more electrons. Each covalent bond adds one electron to its outer shell. Therefore, nitrogen forms three covalent bonds.

When an element exists in two or more forms in the same physical state, it exhibits allotropy or allotropism. Allotropy refers to the property of some chemical elements to exist in two or more different forms, known as allotropes, in the same physical state (solid, liquid, or gas). Allotropes are different forms of the same element that have different physical properties but the same chemical properties. Examples of elements that exhibit allotropy include carbon (graphite, diamond), sulphur etc

An atom containing 8 valence electrons is typically classified as a noble gas. Noble gases are found in Group 0 of the periodic table and are known for their stability due to having full valence shells, which means they possess eight electrons in their outermost shell.

In the blast furnace during iron extraction, limestone acts as a flux, reacting with impurities like silicon dioxide (sand) to form a molten slag that can be easily separated from the molten iron. A flux is a substance added to a smelting process to react with and remove impurities from the molten metal. In the blast furnace, limestone (calcium carbonate, CaCO\(_3\)) decomposes at high temperatures into calcium oxide (CaO) and carbon dioxide (CO\(_2\)). The calcium oxide (CaO) then reacts with the silicon dioxide (SiO\(_2\)), which is a common impurity in iron ore, to form calcium silicate (CaSiO\(_3\)), which is the molten slag.

A monomer is a small, basic building block molecule that can bond with other similar molecules to form a larger, more complex molecule called a polymer. The monomer of polythene (also known as polyethylene) is ethylene (ethene), a gaseous hydrocarbon with the chemical formula C\(_2\)H\(_4\).

The oxidation of ethanol involves two steps: first, ethanol is oxidized to acetaldehyde (ethanal), and then acetaldehyde is further oxidized to acetic acid (ethanoic acid). Ethanol (CH\(_3\)CH\(_2\)OH) is oxidized to acetaldehyde (CH\(_3\)CHO). This process involves the removal of a hydrogen atom from the carbon atom that is bonded to the alcohol group (-OH). Acetaldehyde (CH\(_3\)CHO) is then further oxidized to acetic acid (CH\(_3\)COOH). This involves the addition of an oxygen atom to the carbon atom that is bonded to the aldehyde group (-CHO). Strong oxidizing agents like acidified potassium dichromate (K\(_2\)Cr\(_2\)O\(_7\)) or alkaline potassium permanganate (KMnO\(_4\)) are commonly used to oxidize ethanol.

Tetraoxosulphate(VI) acid, also known as sulfuric acid (H₂SO₄), is considered a heavy chemical because it is produced and used on a large industrial scale and is a key raw material in many industries. It serves as a crucial raw material in various industries, including fertilizer production, manufacturing of explosives, dyes, and other chemicals.

C\(_5\)H\(_{12}\) has three (3) isomers which are; - pentane, - 2- methyl butane and - 2,2-dimethyl propane.