Draw a valid Lewis structure for each ion: (a) OH −; (b) H 3O +.

(b) Methyl azide, CH-N3 is a molecule that decomposes explosively. Draw a Lewis structure for CH3N3, showing formal charges and also sketch any possible resonance forms.

Write Lewis structures for the following: (a) H2CO (bothH atoms are bonded to C), (b) H2O2, (c) C2F6 (contains a C¬C bond), (d) AsO33- , (e) H2SO3 (H is bonded to O), (f) NH2Cl.

Draw a Lewis structure for (a) PF₃; (b) H₂CO₃(both H atoms are attached to O atoms); (c) CS₂.

Keeping in mind that some elements violate the octet rule, draw a Lewis structure for each compound: (a) BCl 3; (b) SO 3.

Write Lewis structures for the following molecules and ions:   (a) NCl3, (b) OCS, (c) H2O2

(a) Which of the following atoms is never found with morethan an octet of valence electrons around it? S, C, P, Br, I.(b) Draw the Lewis structure for XeF2.

Common exceptions to the octet rule are compounds and polyatomic ions with central atoms having more than 8 electrons around them. Phosphorus pentafluoride, PF5; sulfur tetrafluoride, SF4; xenon tetrafluoride, XeF4; and tri-iodide ion, I3, are all examples of exceptions to the octet rule. (a) Draw the Lewis structures of these substances.(b) For which elements in these substances can theatoms have more than 8 electrons around them?(c) How can the atoms of the elements youidentified in Part (b) be surrounded by morethan 8 electrons?

Calculate the enthalpy change for the following reactions using the bond enthalpy given below. (Bond enthalpy/kJ : H−H = 436, C−H = 413, C=O = 799, O=O = 495, O−H = 463) (a)  H2(g) + 1⁄2O2(g) → H2O(g) (b)  CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)