Nov 11

Homework, Due Tuesday, November 12th

1.  Use the following terms in the same sentence: element and pure substance

2.  A metalloid:

a. may conduct electric current

b. can be ductile

c. is also a semiconductor

d. all of the above

3.  What is a pure substance?

4.  There are eight elements which make up 98.5% of the Earth’s crust: 46.6% oxygen, 8.1% aluminum, 5.0% iron, 3.6% calcium, 2.8% sodium, 2.6% potassium, and 2.1% magnesium.  The rest is silicon.  What percentage of Earth’s crust is silicon?

6.  Compare the properties of metals, nonmetals and metalloids.