Homework: Atomic Structure

1. One isotope of a metallic element has mass number 65 and 35 neutrons in its nucleus. Write the symbol for this isotope.
2. Fill in the blanks in the following table (all atoms have a charge of zero):

   Name	Symbol	Z No. of p+	A - Z No. of n0	A Mass	No. of e–
   iron-54	5426Fe
   		5	6
   			16		15
   		79	117		79
   radon-222			136

3. One isotope of a nonmetallic element has mass number 127 and 74 neutrons in its nucleus. Write the symbol for this isotope.
4. Which of the following symbols provides more information about the isotope? ²⁴    Mg or   ₁₂Mg? Explain.
5. Fill in the following table.

   Name	Symbol	Z No. of p+	A - Z No. of n0	A Mass	No. of e–
   		5	5
   		7	7
   		19	18
   		30		66
   		35		81
   		35		79
   		19		39
   			24	46
   			28	50
   			64	111

6. What number do all atoms of an element have in common? What number can be different and allow the atom to still be the same element?
7. What are atoms of the same elements with different mass numbers called?

8. You have learned about the parts of atoms. Now remember what you have learned about sub-atomic particles. Fill in the following table with the mass expressed in atomic mass units (amu).
   

   	Mass	Symbol	Charge
   proton
   neutron
   electron

9. What is the definition of atomic mass? Give the average atomic mass of H, C, N, O, Cl, and Ca.
10. What is a period in the periodic table? How many are there?
11. What is a group in the periodic table? What do you know about the chemical and physical properties of the elements in a group?
12. Compare and contrast the positions of Democritus and Aristotle on the matter of the ultimate nature of matter.
13. Give two examples of each of the following: non-metals, transition metals, halogens, alkali metals, and alkaline earth metals.
14. Why are the elements placed in the periodic table in order by atomic number and not atomic mass?