The formal charge is the "charge" an element would have in a molecule or ion if all of the bonding electrons were shared equally between atoms. We can draw three inequivalent Lewis structures for the thiocyanate ion , SCN". The concepts of formal charge and electronegativity can help us choose the structure that is the most significant representation. 1. Assign formal charges to the elements in each of the structures below. [-c=n:] [-c=#] [is=c =C= :S = C-N: Formal Charge S C N

CH4 (g) reacts with F2 (g) to produce CH3F (g) and HF (g)

use bond energies to estimate the H for the following reaction. State wethere the reaction is endothemic or exothemic, and the state whether tthe reactant or product bond are stronger( on average). Frist draw the lewis structure of each molecules. nh2-nh2(L) + 2F2(g) --> N2(g) + 4HF(g)

3. Arrange the following ionic compounds in order of increasing lattice energy: NaF, Csl, and CaO.

Acetylene gas (ethyne; HC=CH) burns with oxygen in an oxyacetylene torch to produce carbon dioxide, water vapor, and the heat needed to weld metals. The heat of combustion for acetylene is -1259 kJ/mol. Calculate the C=C bond energy. The average bond energies (kJ/mol) C-H 413 C-C 347 C=C 620 H—H 436 kJ/mol -0 142 0=0 498 H-O 467 351 C=0 799

Determine the formal charge for the atom indicated in the structures below. ASSUME that the structures are drawn correctly and that you do not have to change them due to formal charge issues. The external atom in this structure. :O: :O! Ar 11 :0: The central atom in this structure. = :0: (1 Si = : 0: 2- 1. +1 2. +2 3. +3 4. 0 5. -3 6.-2 7. -1

The formal charge is the "charge" an element would have in a molecule or ion if all of the bonding electrons were shared equally between atoms. Use the References to access important values if needed for this question. We can draw three inequivalent Lewis structures for dinitrogen monoxide, N₂O . The concepts of formal charge and electronegativity can help us choose the structure that is the most significant representation. 1. Assign formal charges to the elements in each of the structures below. Formal Charge N₁ N₂ :N,=N,-O: || A N=N,=Ô N-N,=O: C 2. The structure that contributes most significantly to the overall electronic structure of N₂O is ↑ Formal Charge

1 I I 1 I I 1 I I I I I I I I I 1 I I I I 1 I I I 2. Use Lewis Dot Diagrams to show the bonding between carbon and chlorine. 3. Is the bonding between sodium and fluorine ionic or covalent? I I I I

Only typed solution

Write the Lewis symbols for the ions in each ionic compound.a. SrO b. Li2S c. CaI2 d. RbF