Question

26. Examine the Lewis structure below. If it is a correct structure for formaldehyde, CH20, explain how it obeys the rules of drawing Lewis structures. If not, explain which rule(s) it does not follow and draw the correct structure. Please include at least 3 complete content related sentences. (ref: p.253-260) H:0:0: 27. Why is PCs an exception to the octet rule, while PCI, is not? Please use at least ONE complete content related sentence. (ref:p.265-270)

Answer 1

Howrong) 4:C::0. C=0 correct dot structure. This Lewis is not a correct c- 6- 15 25 2p² excited state 15 es'2p3 Carbon contains 4 single electrons so it forms four bonds. After bond formation x:C: x 4bond pairs bepose bond formation Hese Xe some atom) But in given sit dot structure Carbon has 3 bond bopairs & one lone pair. H:6:0 Carbon atom lone pair (non bonding electron pois so wrong

Also 10-8-15 25 2pt TV 111111 It has two lone pair of electrons & two single electrons. Solt forms two bonds. After bond formation baggen will have two non bonding pair of electrons o two bond pairs non bonding paig ö: bond pairs Before bond formation But in given structure oxygen has 3 lone paix & one bond pairs. H:C: 0 3 lone pairs --> one bond pair so there are two wrongs in the given structure ① Carbon has one lone pair & 3 bond pains, but it should have your bond pair of elections. ② oxygen has 3 lone pairs & one bond pair, but it should have a bond pairs & a lonepairs.

correct structure ix - P- 5-1S 25 20 35 36 I has one lone paisa & 3 single ekotrons. so P forms 3 bonds so phas 3 bond paint & one lone pair lone pain bond pairs .. .P. •c! CEP:c: Pellocosocket T sule :01: 8 2 +6 1x2 + 3x2 3 x 2 + 1x2 - 6+2 =8 bondpair lone point . Bond pain pe cl both Shell so both follows octet sule bave selections in Valency follow octet role.

But in excited state, selections of 3sorbital jumps to 3d orbital so as a result it will have 5 single electrons. P-15- 35 3p² 3d excited state: 35' 3p3 3d 3 il 11111 1DII Now P forms 5 bonds. By each bond it will acquire one electron, so p has now 5x2=10€ in valency shell. So it exceeds 8 electrons. pels doesn't obey octet rule. - 5X2-100 ca sci , ac 3y2 + x 2 26+2=8 simply In pcl - P has 8 electron in valency shell. so it obey follows octet rule But in pas phas 10 eleton in valeny Shell. s PC doesn't follow octetsule,