Periodic table+ general periodicity CAQ

🌈 Periodic table Created Tags Halogens State and explain the relative thermal stability of hydrogen halides Thermal stability decreases down the group 17 As HX bond energy decreases as less effective orbital overlapping between orbitals of H atom and halogen atom as size of halogen atom increases resulting in longer and weaker HX bond Hence less energy to break the HX bond decreases HCl does not decompose even on strong heating. 0.5 HBr yields reddish-brown (accept “brownˮ) fumes of Br2 under strong heating. 0.5 HI gives violet fumes of I2 when red‐hot rod is plunged into jar of HI. 0.5 Trend in volatility down the group they have simple molecular structures with weak Iʼd-Iʼd between molecules Down the group, electron cloud size of halogen molecules increases and becomes more easily polarised, leading to stronger London dispersion forces, more energy to overcome the stronger Iʼd-Iʼd, bp increases and volatility decreases June 8 , 2025 119 AM P er iodic t able 1

Transition metal Definitions: Transition metals are d block elements which form one or more stable ions with a partially filled d subshell Ligand: an ion or molecule that contains at least one atom bearing a lone pair of electrons which can be donated into a low-lying vacant orbital of a central metal cation, forming a dative covalent bond A complex contains a central metal cation, bonded ligands by dative covalent bonds Why is copper/ any metal in d block element transition metals? it is a d-block element which forms one or more stable ions with a partially filled d-subshell Questions regarding properties of transition metals Physical properties: Property Explanation Higher mp/mp than non-transition metals transition metal can contribute the3d and 4s electrons for metallic bonding while non- transition metal can only contribute the 4s electrons for metallic bonding. The metallic bond is stronger for transition metal, and hence it has a higher melting and boiling point Higher density Density = mass/volume. Transition metals has a heavier relative atomic mass than non-tm, tm have a smaller atomic radius than non-tm .Hence, there are more tm atoms per unit volume than in non-tm and hence P er iodic t able 2

Property Explanation densities of tm is significantly greater than that of non-tm Similar atomic radii across the period Across the transition elements series, nuclear charge increases and electrons are addedto the inner principal quantum shell 3d subshell). Shielding effect for valence shell 4selectrons increases due to the increase in no. of inner shell (3d) electrons. Nuclearattraction for the valence electrons is almost constant, hence the atomic radii are relativelysimilar. Chemical properties: Properties Explanation Transition metals less reactive Less likely to undergo oxidation unlike group 1 and 2 metals, compare E values Exhibit variable oxidation states Transition elements exhibit variable oxidation states in their compounds due to the close simi