Download Atomic Structure study guide # 1

Chemistry
Atomic Structure
Atomic Structure
Instructions: Study and use the information and diagrams provided to
answer the questions in this packet.
Part A: Structure of the Atom:
white oval = proton (+1 charge)
black oval = electron (-1 charge)
gray oval = neutron (0 charge)


These three particles that make up the atom are called sub-atomic
particles.
The part of the atom where protons are neutrons are located is called
the nucleus.
The following three diagrams represent three different types of hydrogen
atoms:
1
1
H
2
1
H
3
1
H
1. How many protons, neutrons, and electrons does each hydrogen atom
have?
The following three diagrams represent three different types of carbon
atoms:
12
C
6
13
C
14
6
C
6
2. How many protons, neutrons, and electrons does each carbon atom have?
Notice the symbol notation used below each picture on the previous page…
In generic terms…
X = chemical symbol of element
Z = atomic number
A = mass number
X
A
Z
3. Where are the atomic numbers located on your periodic table?
4. Where are the mass numbers located on your periodic table?
Using your answers to questions 1 & 2…
5. In terms of subatomic particles, what information does the atomic
number provide?
6. In terms of subatomic particles, what information does the mass number
provide?
Part B: Isotopes

1
1

H, 2H, 3H are notations that represent isotopes of hydrogen atoms.
12
6
1
1
C, 13C, 14C are notations that represent isotopes of carbon atoms.
6
6
7. In terms of subatomic particles, what changes and what remains the same
in isotopes?
Critical Thinking Questions:
8. What structural characteristic(s) do all hydrogen atoms have in common?
9. What structural characteristic(s) do all carbon atoms have in common?
10. What single characteristic allows you to tell an atom of one element
from an atom of a different element?
11. Define the term isotope?
12. In terms of subatomic particles, how does one isotope of hydrogen
differ from another isotope of hydrogen? How does one isotope of carbon
differ from another isotope of carbon?
Part C: Atomic Mass
The atomic mass unit (amu) is a special unit for measuring the mass of very
small particles such as atoms. Protons and neutrons have a mass of 1 amu,
and electrons have a mass of 0 amu.
20 protons
20 neutrons
13 protons
14 neutrons
40
Ca
27
20
periodic table atomic mass =
40.08 amu
Al
13
periodic table atomic mass =
26.982 amu
Critical Thinking Questions:
13. In atomic mass units (amu), what is the mass of an electron?
14. What is the mass of a proton and a neutron in atomic mass units (amu)?
15. Is most of the mass of an atom located in the nucleus or outside the
nucleus? How do you know?
16. Look at the calcium and aluminum examples above. Notice the mass of
calcium from the periodic table is 40.08 amu (40 amu rounded), and the mass
of aluminum from the table is 26.982 amu (27 amu rounded). Based on the
information in the picture, how was this mass determined?
Part D: Ions
 Ions are atoms of elements with charges, either positive or negative.
Atom
Ion
9 protons
10 neutrons
9 protons
10 neutrons
19
F
F
19 -1
9
9
Atom
12 protons
12 neutrons
Ion
12 protons
12 neutrons
24
Mg
24
12
Mg+2
12
17. What is structurally different about an atom verses an ion?
18. Look at the fluorine atom and fluorine ion example above. How many
protons does each have? How many electrons does each have? Why is the
number of protons the same for both and the number of electrons
different?
19. How do you determine the charge on an ion?
20. Based on atomic structure, why is the charge on a neutral atom zero?
21. An oxygen ion has a charge of -2. How many protons and electrons does
the oxygen ion have?
22. An aluminum ion has a +3 charge. How many protons and electrons does
the aluminum ion have?
Part E: The Periodic Table
Locate the following groups on the periodic table:
a. Li+1, H+1, K+1
d. Ca+2, Ba+2, Be+2
b. Cl-1, F-1, Br-1
e. O-2, S-2
c. N-3, P-3
23. What do you notice about the locations of each group on the table?
24. What do you notice about the locations of the positive ions verses the
locations of negative ions on the periodic table?
25. What is true about the number of electrons gained or lost in the ions in
each individual group?
Practice: You may need to use your periodic table to help you with some of
the questions.
26. What is the element symbol for and number of protons found in each of
the following elements?
a. sodium
b. iodine
c. nitrogen
d. silver
27. How many protons, neutrons and electrons are found in each of the
following?
a.
35
Cl
b.
17
7
Li
c.
3
59
Co
27
28. Another way to represent an element is to write the symbol with a dash
after it and the atomic mass after the dash; X-atomic mass. For example:
for carbon, C-12. How many protons, neutrons and electrons are found in
each of the following?
a. K-39
b. O-16
c. U-238
29. Which of the following choices shows a correct pair of isotopes?
Provide an explanation for your choice.
a.
222
86
86
Rn, 222Rn
d. 222Rn, 223Ra
86
b.
222
Rn, 222Rn
86
87
c.
222
86
Rn, 223Rn
86
88
30. How many protons, neutrons and electrons are found in each of the
following ions?
a. Sr+2
b. P-3
c. Al+3
d. Br-1