Chapter 1 Summary Questions Due Thursday 30 September 2010
1. A
2. D
3. B
4. C
5. C
6a)
Name
Mass
Charge
Proton
1
+1
Electron
1/1836
-1
Neutron
1
0
b) An atom with 11 protons would have 11 electrons.
c) The mass of an atom which has 11 protons and 12 neutrons would be 23.
d) You would find this element in group 1.
7a) In the first level 2 electrons can be put there, in the second level 8 electrons can be put
there and in the third level 8 electrons can be put there.
bi)
bii)
biii)
c) The elements lithium (3) and sodium (11) are both in group 1.
8a)
Name
Carbon -12
Carbon -14
Number of Protons
6
6
Number of Electrons
6
6
Number of Neutrons
6
8
b) We call atoms like these isotopes.
c) Another similar example would be carbon -13 because it has 6 protons and 7 neutrons.
d) The chemical reactions in part A compare because even though they each have a different
amount of neutrons they do not react differently in chemicals. The chemical reaction is caused
by the electrons and since they each have the same number of electrons and they are arranged
the same, each carbon isotope has the same chemical reaction.
9a) In the first isotope that bromine forms the number of protons would be 35 but the number of
neutrons would be 46. This gives the isotope a mass of 81. In the other isotope it would still
have 35 protons but the number of neutrons would be 44 giving the isotope a mass of 79. In
bromine the atomic mass is 80 because there are 35 protons but 45 neutrons. The average of
79 and 81 would give you 80 and that is the atomic mass of bromine.
b) There are 3 bromine molecules with the different masses. (79 & 81, 79 & 79, 81 & 81)
c) You would expect the 79 & 79 molecules to evaporate most quickly from liquid bromine.
10a) 2, 8, 8 show how many electrons are on each energy level of the atom. It belongs to group
0. The last level which contains 8 electrons is usually referred to as the ‘full’ level. This means
that the atom is very stable.
b) This is an unusual atomic particle because if an atomic particle has 11 protons then it should
have 11 electrons. The number of protons is usually the same as the number of electrons in an
atom. It would also mean that the atom is positively charged since there are more protons.
ci) The mass of this particle would be 23.
ii) The overall charge on this particle would be positive.
iii) You would find similar elements in group 1.
11a) One medical use for radioisotopes is to inject people with a faulty thyroid gland with weakly
radiations of iodine. If the gland is not working properly then the radioactivity will spread out
more in the neck.
b) I think that surgery would not be better in this case because doctors can detect the radiation
given off by the radioactive isotopes. With the weakly injections that the doctors inject in the
patient, he or she (the doctor) can see if the thyroid gland is working properly because the
radioactive isotope will be detected in the neck and if not then the radioactivity will spread out.
With surgery you would have to do surgery often to make sure that the right amount of iodine is
in the patient so that the thyroid gland absorbs it. Since the patient has a faulty thyroid gland
you have to do the surgery often.
c) There are strict rules about the use of radioactive materials because too much exposure to
these kinds of materials can cause sicknesses in humans and even death. A lot of exposure to
radioactive materials can cause cancer for example.
d) Carbon dating is when scientists use the carbon which is emitted from fossils and artifacts to
determine how old it is. It is useful because it can show scientists how old something is and how
long it has been around on earth.
12a) The atomic number for fluorine is 9.
b) Mass number means the weight of the atom. It shows how much the atom weighs by adding
together the protons and the neutrons. With fluorine the mass number would be 19.
c) There are 9 protons, 9 electrons and 10 neutrons in a fluorine atom.
d)
13a)
Name
Proton
Neutron
Electron
Iron (Fe)
26
41
92
Niobium (Nb)
30
52
143
Uranium (U)
26
41
92
14a) Isotopes are atoms which have the same atomic number but have a different mass. This is
because they have the same number of protons but a different number of neutrons.
b)
Name
Protons
Neutrons
Electrons
Chlorine- 35
17
18
17
Chlorine- 37
17
10
17
c) In the isotopes chlorine-35 and chlorine-37 the arrangement of the electrons would be 2 on
the first level, 8 on the second level and 7 and the outer level.
15a)
b)
c)
16a) 5
b) 7
c) 4
d) 8
17a) A and F
b) A
c) C
d) B and D
e) Calcium
f) Element F has 82 protons. It is lead (PB)
g)