1. Name Three Elements in Group 7A. How Many Valence Electrons Do These Elements Have?

Name______

101N Group Activity 1

1. Name three elements in group 7A. How many valence electrons do these elements have?

2. Do all atoms of a particular element have the same atomic number?

3. Do all atoms of a particular element have the same mass number??

4. What are the two types of pure substances? Give two examples of each.

5. What are the two types of mixtures? Give two examples of each.

6. What is the difference between formation of a mixture and formation of a compound?

7. Give two reasons why wires are made from metallic rather than nonmetallic elements.

8. How many significant figures are in each of the numbers below?

9. How does one determine the number of significant figures in the answer when doing multiplication/division?

10. How does one determine the number of significant figures in the answer when doing addition/subtraction?

11. Express the following numbers in scientific notation.

a) 95

b) 5,294,000

c) 0.0000610

12. Use conversion factors to determine how many inches are in 2.73 ft. Remember sig figs!

13. Use conversion factors to solve the following problem. A bucket contains 4.55072 gallons of water. How many liters does it contain? Remember sig figs!

14. Use conversion factors to solve the following problem. One gram of hydrogen has 6.02 x 1023 atoms. How many molecules are in 0.81 pounds of hydrogen? Use sig figs and scientific notation when expressing the answer.

15. Use conversion factors to solve the following problem. Brand X corn chips cost $2.95 per pound. These chips contain 37% fat by weight. If you bought $20.00 worth of corn chips, how much fat have you purchased?

16. The temperature on the surface of a nearby planet is –218 degrees Fahrenheit. NASA wants to land a robot probe on the planet, but the probe freezes if the temperature is below –100 deg C. Will the probe freeze? What is the temperature of the planet in degrees Kelvin?

17. What is the difference between mass number of atomic mass?

18. What are isotopes?

19. Complete the following table for neutral atoms:

20. How many sublevels are in the 4th level? How many orbitals are in this level? How many electrons is it possible for the 4th level to contain?

21. Write the electron configurations for the following elements. You may use abbreviated configuration if you choose.

a)  Li

b)  C

c)  S

d)  I

e)  Fe

f)  Cr