Tell me about the element phosphorus?
It is an essential component of living systems and is found in nervous tissue, bones and cell protoplasm. Phosphorus exists in several allotropic forms including white (or yellow), red, and black (or violet). White phosphorus has two modifications. Ordinary phosphorus is a waxy white solid. When pure, it is colourless and transparent.
Why would a less stable molecule give off more heat than a more stable molecule in the same reaction?
First off, no two reactions are the SAME, even if they maybe exceedingly similar. You see slightly different energetics even when the same molecule with two different isotopes of hydrogen are the reactants (e.g. H2O reaction vs. D2O reaction). Therefore, you cannot say that two reactions are the same, when clearly one of the reactants is different.If you mean that two reactions are in the same class or family (e.g. nitration or hydrolysis), then the less stable molecule is a reactant that starts off with a higher potential energy (chemical energy, if you will) and upon reaction will release greater amount of energy to arrive at the product of the reaction.
Why is nitrogen a gas whereas phosphorus is a solid?
Nitrogen is a gas because it is simple diatomic molecule with triple bond between the two nitrogen atoms. Due to its small size and non polar nature, intermolecular forces are absent and it is gas in nature.Phosphorous is found in different allotrpic forms as white, red and black phosphorus. In all of these structures a phosphorus atom is attached with more than two phosphorus atoms (4 in white and polymeric structures in red and black). Due to this extensive bonding phosphorus is found in solid state.
Why are half filled and fully filled orbitals more stable than partially filled orbitals?
The answer is Beautiful Beautiful SYMMETRYAtoms exist in orbitals, and an orbital has two electrons, According to Pauli's exclusion principle, two electrons which exactly identical to each other, hate to be at same place! That is no electrons have the same configuration. So in an orbital which can hold 2 electrons, each electron has an opposite spin. Clockwise and Anti-clockwise which gives it stability. Thats all angular momentum thing conserved here stuff.Thats the background needed.Coming to your question,Now according to Aufbau principle electrons with same spin are filled first. So in a D orbital First five electrons with clockwise spin (say) are filled first. Then the six electron will of anti-clockwise spin which will increase the overall energy of system as electrons with opposite spin repeal each other. Thus we get more stability at fifth electron, or in general at half filled orbital.Same story at completely filled orbitals as Every electron has an counter-part and everyone is happy.Another factor to consider is the exchange energy. Electrons love to roam about, in its sub-shell, and an extra odd anti-clockwise electron will just increase the total energy and decreasing stability.Hope this suffices
Why does nitrogen exist as N2, Phosphorus as P4, and Sulfur as S8?
Nitrogen is the anomaly, along with oxygen, because first row elements can form stable [math]\pi[/math] bonds.Sulfur is isoelectronic to oxygen, just as phosphorus is to nitrogen. But sulfur and phosphorus cannot form stable [math]\pi[/math] bonds to themselves, and so they exist as single bonded allotropes. S2 and even P2 exist, but only transiently because they are quite unstable with respect to single bonded forms.Phosphorus can form a P4 white phosphorus tetrahedron because it can form three bonds, while sulfur can only form two bonds. Therefore sulfur forms rings and chains only.The most stable allotrope of phosphorus, red phosphorus, is a cross-linked, polymeric chain of atoms.
Reaction Rate Problem! Help please.?
Look at the molar ratio between 4PH3 and P4 and 6H2. When 4 moles of PH3 are consumed, one mole of P4 forms, so one fourth of .0048 moles will be created each second of P4 or .0012 moles per second in a 2 liter container, or .0006 moles per liter per second is the rate production of P4. When 4 moles of PH3 is consumed, 6 moles of hydrogen is produced, so when .0048 moles PH3 is consumed, then l.5 times as many moles per second of H2 is produced in a 2 liter container, or .0072 moles /sec/2 liters or .0036 moles/liter/second H2 is produced.
Explain in terms of stabilities of sigma and pi bonds?
You mean S8 as the most common form of sulfur. These are some of the more obvious results of a somewhat general trend -- the 2nd period elements like O, N, and to a lesser extent C are very good at forming pi-bonds. In fact, contrary to usual dogma, the pi bonds in N2 and O2 are actually stronger than single bonds for those elements (for reasons that are often explained using some handwavy waffle about lone pairs, but you really need MO theory to make proper sense of it). In contrast, elements like Si, P, and S make extremely poor pi-bonds to themselves, and only marginally decent pi-bonds even to oxygen. Some other examples: CO2 is a molecular gas with C=O double bonds, SiO2 forms only single bonds in an extended network, forming quartz. Similarly, acetone is Me2C=O, silicone is a polymer of -[-O-SiMe2-]- single bond linkages. [NO3]– is a discrete molecular ion with delocalized N=O pi bonding, [PO4]3– tends to associate in chains of tetrahedra with extra single bonds and reduced pi-bonding (as seen in ATP, for example). SO3 exists in equilibrium with a trimeric form that has a ring of S-O-S-O-S-O- single bonds. NO is a stable diatomic compound, NS forms a weird associated tetrameric complex with a puckered ring of S-N-S-N- links. Basically what you're looking at is thermodynamics of the bonds you're choosing between. Compare N2 associating to form either a hypothetical N6 ring (analogous to HCCH trimerizing to form benzene, which is downhill) or the N4 tetrahedra similar to what phosphorus does. To do that reaction, you need to break one (or two) pi bonds per N2, and form two new sigma bonds. If the two sigma bonds are stronger, it does that. If the pi-bond is stronger, it won't. Pi is a very strong bond for N, and N-N single bonds are unexpectedly weak, so that's a bad deal. N2 stays a diatomic molecule with a triple bond. pi bonds are terrible for P, the single bonds are OK, so P2 isn't stable, forming the tetrahedra instead. Similarly, pi-bond in O2 is great, single O-O are weak, so O2 is a discrete molecule; the reverse is true for S, so you get rings and chains of S atoms under normal conditions.
Why does N2 exist as gas but phosphorus exist as a solid?
N2 exists as a gas because there is a triple bond between two N atoms.N—N single bond is weak since N is small and the lone pairs on N undergo interelectronic repulsion so N2 exists as a discrete molecule.P on the other hand is larger and the lone pairs on P do not experience interelectronic repulsion hence P—P single bond is strong and exists as P4 units.So N2 is a gas but P4 is a solid.
The stable allotroph of phosphorus is?
-- never heard of vioet phosphorus -- white P is just 1 tetrahedral unit, so unstable nd very reactive answer can't be White P -- red P is more stable than White as it is tetrahedral units joined together like a chain, so extra stability -- dunno about black P {sorry} so, answer cud be black or red