Bonding Chem 20

 Ionic Bonding        [pic 1]

1. Write Lewis symbols for the following atoms. Label bonding electrons and lone pairs of electrons. Label each element as metal or non-metal

1. silicon                     b.  rubidium                   c.  barium                         d.  tin                     e.  iodine               f.   arsenic

1. Complete the following table.

1. Use Lewis symbols to represent the formation of the ionic compound formed when the following elements combine. Name the compound formed, give its chemical formula, and show the Lewis Structure of the formula unit.

1. strontium and fluorine

1. magnesium and chlorine

1. sodium and oxygen

1. aluminum and nitrogen

1. Explain the term ‘ionic bond’.

1. What is the key theoretical process used to explain the formation of ionic compounds? What is believed to be the reason for this process?

1. What is the most direct evidence for the presence of ions in ionic compounds?

1. How does the electronic configuration change when sulphur forms the S2- ion?

1. Draw the Lewis Symbols for each element of Period 2.

1. What is the octet rule?

Molecular Bonding[pic 2]

[pic 3][pic 4][pic 5][pic 6][pic 7][pic 8][pic 9]

[pic 10][pic 11][pic 12][pic 13][pic 14][pic 15][pic 16][pic 17][pic 18]

Shapes of Molecules[pic 19]

For each of the following molecules, draw the 3-D diagram (stereochemical diagram) and name the shape around each central atom.

1. hydrogen iodide, HI                                        2. silane, SiH4

3. phosphine, PH3                                        4. formaldehyde, H2CO

5. hydrogen peroxide, H2O2                                6. ethyne, C2H2

7. hydrazine, N2H4                                        8. propane, C3H8

9. methylcyanide, CH3CN                                10. ethanol, CH3OH

[pic 20]

Electronegativity and Polarity

Comparing Electronegativities of Atoms

The shared electrons in a covalent bond will be displaced (more strongly attracted) to which atom in each of the following chemical bonds? (the first is done as an example. These diagrams represent bonds only – not molecules)

                       →

Example:  H  –  F           The arrow indicates the shared electron pair is attracted more strongly

                 2.1   4.0        by the fluorine atom.

1.      N – H                        2.    B – F                3.  S – O                4.   P – H

5.    Si – Cl                        6.  Cu – Br                7.  N – I                8.  Br – Cl

9.    C – H                        10.  O – H                11. C – Cl                12.  C – O

13. List the elements of period 2 and their respective Pauling electronegativities.