Group 17 of periodic table consists of five elements, i.e., fluorine, chlorine, bromine, iodine and astatine. These elements are called Halogens. Fluorine is most reactive and hence is also called super halogen. Astatine is radioactive and hence occurs in nature only in traces.
The elements of Nitrogen family i.e. group 15 of the periodic table are: nitrogen (N), phosphorous (P), arsenic (As), antimony (Sb) and bismuth (Bi). Collectively, group 15 elements are called pnictogens and their compounds are called pniconides. (It means suffocation producing elements)
Coordination compounds are the compounds in which the central metal atom is linked to a number of ions or neutral molecules by coordinate bonds, i.e., by donation of lone pairs of electrons by these ions or neutral molecules to the central metal atom.
When a hydrogen atom in a hydrocarbon (aliphatic or aromatic) is replaced by one or more —OH group , the compound is known as alcohols or phenols. In other words, hydroxy derivatives of aliphatic hydrocarbon are called alcohols while hydroxy derivatives of benzene are called phenols.
Polymers or macromolecules are very high molecular mass (10 3 – 107 u) substances each molecule of which consists of a very large number of simple repeating structural units joined together through covalent bond in a regular fashion.
Haloalkane and Haloarene are obtained by the replacement of a hydrogen atom of an alkane and arene respectively by a halogen atom (F , Cl , Br , I ) . Haloalkane contain halogen atom attached to the sp3 hybridised carbon atom of an alkyl group whereas haloarenes contain halogen atom attached to sp2 hybridised
D- block elements are called transition elements since they have unpaired electrons in their d orbital.
Elements in which last electron ( also called differentiating electron ) enters the ante-penultimate energy level are called F-Block elements . These elements have also been called inner transition elements