Group 15 Elements: The Pnictogens

Group 15 elements, commonly known as the Nitrogen family, include nitrogen, phosphorus, arsenic, antimony, and bismuth.

As you move down Group 15, the elements transition from gases (nitrogen) to metalloids (arsenic, antimony) and finally to metals (bismuth).

The valence electron configuration of Group 15 elements is ns2np3.

<p>The first ionization energy generally decreases as you move down Group 15, from nitrogen (1402 kJ/mol) to bismuth (703 kJ/mol).</p> Signup and view all the answers

<p>Electronegativity decreases from nitrogen (3.0) to bismuth (1.9) as you move down Group 15.</p> Signup and view all the answers

<p>Phosphorus commonly exhibits oxidation states of +5, +3, and -3.</p> Signup and view all the answers

<p>The melting points vary significantly, with nitrogen at -210°C and bismuth at 271°C, showing an increasing trend as you move down the group.</p> Signup and view all the answers

<p>The atomic radius increases from nitrogen (56 pm) to bismuth (143 pm) as you move down the group.</p> Signup and view all the answers

<p>The tendency decreases due to lower ionization enthalpy and electronegativity associated with an increasing atomic radius.</p> Signup and view all the answers

<p>The inert pair effect refers to the tendency of the s-electrons to remain non-bonding, leading to a decrease in the stability of the +5 oxidation state while increasing the stability of the +3 state.</p> Signup and view all the answers

<p>Group 15 is classified as p-block because its elements have valence electrons in the p-orbitals.</p> Signup and view all the answers

<p>Nitrogen is a strong oxidizing agent and forms primarily a +5 oxidation state, while phosphorus is more stable in its +5 state and less reactive.</p> Signup and view all the answers

<p>Nitrogen and phosphorus are nonconductors, while arsenic shows semimetallic behavior, and antimony and bismuth exhibit weakly metallic behavior.</p> Signup and view all the answers

<p>The N=N triple bond requires considerable energy to break, making the higher oxidation states of nitrogen less stable compared to its lower ones.</p> Signup and view all the answers

<p>Phosphorus can utilize its d orbitals to stabilize its +5 oxidation state, allowing it to form compounds like PF3 and PF5, whereas nitrogen primarily forms NF3.</p> Signup and view all the answers

<p>Phosphorus's +5 oxidation state is more thermodynamically stable than nitrogen's due to its ability to engage d orbitals for bond formation.</p> Signup and view all the answers

<p>The stability of dinitrogen is primarily due to the very high strength of the nitrogen-nitrogen triple bond.</p> Signup and view all the answers

<p>Nitrogen forms stable dinitrogen due to strong triple bonds, while phosphorus forms reactive singly bonded groups because of weaker phosphorus-phosphorus bonds.</p> Signup and view all the answers

<p>Dinitrogen being a gas contributes to a favorable entropy change, enhancing its formation in reactions.</p> Signup and view all the answers

<p>Nitrogen's smaller size limits its ability to accommodate more than three fluorine atoms, unlike larger phosphorus.</p> Signup and view all the answers

<p>The bond strength difference between the triple and single nitrogen bonds leads to a preference for forming the stable dinitrogen molecule.</p> Signup and view all the answers

<p>The higher electronegativity of nitrogen (3.0) compared to hydrogen (2.1) results in multiple negative oxidation states for nitrogen compounds.</p> Signup and view all the answers

<p>Key oxidation states of nitrogen include -III (in NH3), -II (in N2H4), and +V (in HNO3).</p> Signup and view all the answers

<p>The nitrogen-nitrogen triple bond strength is greater than that of the carbon-carbon triple bond, while its single bond is weaker than carbon's single bond.</p> Signup and view all the answers

<p>The s-orbital is completely filled while the p-orbitals are half filled.</p> Signup and view all the answers

<p>Atomic and ionic radii increase due to the addition of new orbitals.</p> Signup and view all the answers

<p>Ionization energy decreases because the atomic radius increases, reducing the nuclear hold on outer electrons.</p> Signup and view all the answers

<p>Electronegativity decreases due to the increasing atomic size and distance between the nucleus and the valence shell.</p> Signup and view all the answers

<p>Nitrogen is a gas, while the others are solids, with increasing metallic character from non-metals to metals.</p> Signup and view all the answers

<p>Boiling points generally increase due to larger atomic sizes and stronger intermolecular forces.</p> Signup and view all the answers

<p>The common oxidation states are -3, +3, and +5.</p> Signup and view all the answers

<p>The small increase is due to the presence of completely filled d and/or f orbitals in the heavier members.</p> Signup and view all the answers