Pw d and fblock

• Transition elements are metals with incomplete D subshells in their neutral state or in their highest stable oxidation state
• Zinc, cadmium, and mercury are not considered transition elements because their D orbitals are completely filled in their neutral states
• Transition elements have high melting and boiling points due to strong metal-metal bonding from a high number of unpaired electrons in the D orbital
• Transition elements with more unpaired electrons have higher melting and boiling points due to increased interatomic metallic bonding
• Chromium and molybdenum exhibit abnormal electronic configurations to achieve extra stability with unpaired electrons in their D orbitals
• Molybdenum is the only element in the D block with no electrons in the S orbital, leading to its exceptional catalytic properties
• Chromium and copper have abnormal electronic configurations with unpaired electrons for increased stability
• Transition elements with more unpaired electrons require higher energy for atomization due to stronger metal-metal bonding
• Chromium and molybdenum have the highest enthalpy of atomization due to the maximum number of unpaired electrons in their D orbitals
• Atomic radius decreases across a period in the transition elements due to increased nuclear charge and effective nuclear charge
• Transition elements with more unpaired electrons have smaller atomic radii due to increased nuclear attraction
• Chromium and molybdenum have the smallest atomic radii in their respective series due to the high number of unpaired electrons
• Atomic radius trend:

  • As you move from left to right across the periodic table, the atomic size decreases
  • However, after reaching a certain point, the trend becomes more constant
  • In the transition metals, specifically in Fe, Co, Ni, and sometimes Mn, the difference in sizes is not significant
  • The number of electrons in the D orbital plays a crucial role in this trend
• Effect of increasing D electrons on atomic size:

  • Up to manganese (D5), the number of D electrons is relatively stable
  • Past manganese, the number of D electrons increases to D6, D7, and D10
  • The increase in D electrons leads to electron repulsion, causing the atomic size to be larger than expected
• Size trend in D block elements:

  • Moving from top to bottom in the periodic table, the atomic size increases
  • However, in the transition from 3D to 4D elements, the size increases as expected
  • But from 4D to 5D elements, such as from titanium to hafnium, the size does not increase significantly due to lanthanide contraction
• Color of D block compounds:

  • D block compounds exhibit color due to electron transitions between orbitals
  • Charge transfer between metal and ligands can also lead to color in compounds
  • Compounds without unpaired electrons do not exhibit color
• Oxidation state and stability:

  • Metals prefer their neutral form over the 2+ charged state
  • M2+ species act as oxidizing agents due to their reduction process
  • Stability of oxidation states is influenced by factors like enthalpy of atomization, ionization energy, and hydration energy
• Copper ion stability:

  • In the gas phase, Cu+ should be more stable than Cu2+
  • However, in aqueous solution, Cu2+ is more stable due to higher hydration energy
  • The positive E not value for the transformation of Cu to Cu2+ in water indicates its stability in the aqueous environment
• Copper solid needs high energy to transform into Copper 2+
• Copper metal does not change to Copper 2+ when dipped in water
• Copper 2+ will try to reduce itself and become metal in water
• Copper metal remains in its metallic form and is used in electric appliances because it does not react with water
• Copper 2+ will always try to reduce itself and become metal in water
• Copper metal reacts with HCL to produce hydrogen gas
• Copper metal does not want to undergo oxidation, the process of Copper to Copper 2+ has a negative E value
• Copper 2+ to Copper has a positive E value
• Copper 2+ will immediately accept two electrons and become Copper metal
• Potassium dichromate (K2Cr2O7) is an orange compound
• Heating potassium dichromate with a heat gun turns it into a brown or green color mass
• Potassium dichromate can be used to create a volcanic eruption-like reaction
• Potassium dichromate is prepared by fusing chromite with sodium or potassium carbonate in the presence of oxygen
• Potassium dichromate is a strong oxidizing agent and is used in organic chemistry
• Potassium dichromate can oxidize iodide to iodine and Fe2+ to Fe3+
• Potassium permanganate (KMnO4) is prepared by fusing pyrolusite with alkali metal hydroxide and an oxidizing agent like KO3
• Potassium permanganate is a strong oxidizing agent and can oxidize various substances
• Potassium permanganate can be converted to its higher oxidized species like KMnO4 with acid treatment
• Potassium permanganate is dark purple in color and dissolves in water to give a purple solution
• Heating potassium permanganate causes it to decompose to lower oxidation state compounds
• Potassium permanganate is diamagnetic and has an intense color
• Potassium permanganate is a strong oxidizing agent and can undergo various oxidation state changes