1. Week 3
1. Select the particle or particles that account for more than 99.99% of the mass of atoms other than hydrogen.
Protons only
Electrons only
Protons and neutrons
Electrons and neutrons
2. Which of the following elements has the fewest total number of electrons?
Nitrogen (N) c. Helium (He)
Sodium (Na) d. Lead (Pb)

2. 4. Which of the following is an element?
3. An atom of neon (Ne) has 10 protons, 10 neutrons, and 10 electrons. What is the atomic mass of neon?
0 amu C. 20 amu
10 amu D. 30 amu
4. Which of the following is an element?
Water
Ozone
Oxygen
Carbon dioxide

3. 5. Which of the following is NOT a property of most metals?
Solid at room temperature
Have luster
Conduct heat and electricity well
Do not react readily with any other elements
6. Which of the following is NOT true of noble gases?
Except for helium, they have 8 electrons in their outer shell
They do not react readily with other elements
They usually exist as ions
They are in Group 18 (VIIIA)

4. 7. How many electrons fit into the first energy level or shell?
2 D. 8
8. Select the best statement about different isotopes of an element.
Same number of protons and same number of neutrons.
Same number of protons but different number of neutrons.
Different number of protons but same number of neutrons.
Different number of protons and different number of neutrons.

5. 10. Which statement describes how hydrogen-1 and hydrogen-2 differ?
9. All of the elements in the halogen family
Need to give up one electron to become stable
Need to gain one electron to become stable
Do not react at all with other elements
Do not need to gain one electron to become stable.
10. Which statement describes how hydrogen-1 and hydrogen-2 differ?
Hydrogen-2 has more protons that hydrogen-1
Hydrogen-2 has more electrons than hydrogen-1
Hydrogen-2 has a higher atomic number than hydrogen-1
Hydrogen-2 has more neutrons and more mass than hydrogen-1.