الأحد، 30 مارس 2014

Chapter 7

Questions :

1. Briefly describe the significance of Mendeleev's periodic table.

Because of two main reasons :
     1- It grouped the elements together more accurately , according to their properties .
     2- It made it possible to predict the properties of several elements that had not yet been discovered .

2. What is Moseley's contribution to the modern periodic table?

It grouped elements according to the increasing of atomic number .

3.Classify each of the following elements as a metal, a nonmetal, or a metalloid: As, Xe, Fe, Li, B, Cl, Ba, P, I, Si.

As : Metalloid
Xe : Nonmetal
Fe : Metal
Li : Metal
B : Metalloid
Cl : Nonmetal
Ba : Metal
P : Nonmetal
I : Nonmetal
Si : Metallloid

4. Compare the physical and chemical properties of metals and nonmetals.

Metals tend to be :

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