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Unit I: A Review of Basic Principles

1. What is the major contribution of each person listed to the histroy of the atom?

1. Thomson - discovered the electron using a cathode ray tube.

2. Bohr - states that the electron cloud is broken up into electron energy levels or shells.

3. Chadwick - discovers the neutron in 1932.

2. John Dalton proposed the "Atomic Theory". What are the 5 major points of the theory?

1. All matter is made of atoms.

2. Identical atoms are of the same material. Different atoms, different materials.

3. Attractive forces hold atoms together.

4. There is a amount of space seperating atoms from one another.

5. Atoms are in constant motion.

3. Complete the following table:

Symbol

electron configuration

VSOD

Al

1s2 2s2 2p6 3s2 3p1 see teacher

O

1s2 2s2 2p4 see teacher

Fe

1s2 2s2 2p6 3s2 3p6 4s2 3d6 see teacher

W

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d4 see teacher

As

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3 see teacher

 

4. List four different types of bonds/forces which form between atoms and explain each of them.

1. Ionic Bond - A positive and negative attraction between cations and anions.

2. Covalent Bond - The sharing of electrons between two atoms of high electronegativity.

3. Metallic Bond - The weak sharing of electrons between two atoms of low electronegativity.

4. Intermolecular Forces - The weak attraction found between the atoms of molecules.

 

5. What does VSEPR stand for and what does the theory state?

Valence Shell Electron Pair Repulsion - determine the spacial angles between atoms on a molecule. Every atom has electrons which repel against the electron cloud of a neighboring atom.

 

6. For the following molecules: PF3 , TeCl4 , CuCl2 , NO2

a) Show the electron configuration.

b) Show the valence shell orbital diagram.

c) Show the bonding on the VSOD.

d) What is the hybridization on the central atom?

e) Draw the lewis dot diagram.

f) Identify all polar bonds based on electonegativity calulations.

g) Is the molecule polar ?

h) Identify the shape of the molecule.

PF3

 

 

 

 

A Review of Basic Principles : Answers