Chem 1010 Tutorials
Fall 2013
Tutorial 2A – Atoms, Isotopes and Ions
1.
An isotope with mass number 81 has eleven more neutrons than protons. This is an isotope of which
element?
2.
Fill in the blanks in the table:
Symbol
Element
Name
Atomic
Number
Period
Number
Group
Number
Group Name
Ionic Charge
Ne
4
Alkali Metals
Strontium
3.
3
17
# of Protons
# of Electrons
Fill in the blanks in the table:
Symbol
81
35
Atomic
Number
Mass
Number
35
17
35
63
153
# of Neutrons
Charge
44
0
–1
Br
92
210
82
92
143
0
Pb
108
46
10
9
61
10
Ba2
130
56
Sc 3
45
21
31
15
P 3
ANSWERS:
1.
The element is Bromine
2.
Atomic
Number
10
19
38
17
Period
Number
2
4
5
3
Symbol
Element Name
Group Number
Group Name
Ionic Charge
Ne
K
Sr
Cl
Neon
Potassium
Strontium
Chlorine
18
1
2
17
Noble Gases
Alkali Metals
Alkaline Earth Metals
Halogens
None
+1
+2
–1
Symbol
Atomic Number
35
35
17
92
63
Mass Number
81
79
35
235
153
# of Protons
35
35
17
92
63
# of Electrons
35
35
18
92
63
# of Neutrons
46
44
18
143
90
Charge
0
0
–1
0
0
Ba2
82
47
9
56
210
108
19
130
82
47
9
56
82
46
10
54
128
61
10
74
0
+1
–1
+2
Sc 3
21
45
21
18
24
+3
P 3
15
31
15
18
16
–3
3.
81
35
Br
79
35
Br
35
17
Cl 
235
92
U
153
63
Eu
210
82
Pb
Ag 
108
47
19
9
130
56
45
21
31
15
F