Chapter 2 Assessment (20/20)
1. If the atomic number of chlorine is 17 and the mass number is 35, how many neutrons
are there in the nucleus?
a. 17
b. 18
c. 35
d. 70
2. Both 18O and 16O are found in nature. However, 16O is the most common. Therefore,
a. 18O is the form of oxygen that provides living cells with life.
b. oxygen atoms can have eight or 10 neutrons.
c. only the common form of 16O can bond with hydrogen atoms to form H2O.
d. these are different elements.
e. 18O has two additional electrons in its outer shell.
3. If an element contains eight electrons how many electrons will be placed in the second
valence shell?
a. 2
b. 5
c. 8
d. 6
e. 11
4. What relationship can be determined from the following information:
● The radioactive isotope iodine 131 has a half-life of 8.1 days and emits 0.8 MeV
(milli-electronvolts) of energy.
1. If the atomic number of chlorine is 17 and the mass number is 35, how many neutrons
are there in the nucleus?
a. 17
b. 18
c. 35
d. 70
2. Both 18O and 16O are found in nature. However, 16O is the most common. Therefore,
a. 18O is the form of oxygen that provides living cells with life.
b. oxygen atoms can have eight or 10 neutrons.
c. only the common form of 16O can bond with hydrogen atoms to form H2O.
d. these are different elements.
e. 18O has two additional electrons in its outer shell.
3. If an element contains eight electrons how many electrons will be placed in the second
valence shell?
a. 2
b. 5
c. 8
d. 6
e. 11
4. What relationship can be determined from the following information:
● The radioactive isotope iodine 131 has a half-life of 8.1 days and emits 0.8 MeV
(milli-electronvolts) of energy.
