Review: Atoms
Name: ____Mr. John_____________
Date: ____KEY______________
1. The 3 particles of the atom are:
a. proton
b. neutron
c. electron
2. Their respective charges are:
a. positive
b. neutral
c. negative
3. The number of protons in one atom of an element determines the atom’s identity, and the number of
electrons determines its electrical charge.
4. The atomic number tells you the number of protons in one atom of an element. It also tells you the number
of electrons in a neutral atom of that element. The atomic number gives the “identity “of an element as well
as its location on the Periodic Table. No two different elements will have the same atomic number.
5. The atomic mass of an element is the average mass of an element’s naturally occurring atoms, or isotopes,
taking into account the percentage of each isotope.
6. The atomic mass of an element is the total number of protons and neutrons in the nucleus of the atom.
7. The mass number is used to calculate the number of neutrons & electrons in one atom of an element. In
order to calculate the number of neutrons you must subtract the atomic number from the atomic mass.
8. Give the symbol and number of protons in one atom of:
Lithium Li, 3____________
Bromine Br, 35___________
Iron Fe, 26________________
Copper Cu, 29___________
Oxygen O, 8_____________
Mercury Hg, 80____________
Krypton Kr, 36__________
Helium He, 2_____________
9. Give the symbol and number of electrons in a neutral atom of:
Uranium U, 92______________ Chlorine Cl, 17________________ Boron B, 5_______________
Iodine I, 53_________________ Antimony Sb, 51______________
Xenon Xe, 54____________
10. Give the symbol and number of neutrons in one atom of:
(To get “mass number”, you must round the “atomic mass” to the nearest whole number)
Barium Ba, 81______________ Bismuth Bi, 126_____________
Carbon C, 6________________
Hydrogen H, 0_____________
Fluorine F, 10_______________
Magnesium Mg, 12__________
Europium Eu, 90___________
Mercury Hg, 121____________
11. Name the element which has the following numbers of particles:
a. 26 electrons, 29 neutrons, 26 protons Iron, Fe________
b. 53 protons, 74 neutrons Iodine, I__________________
c. 2 electrons (neutral atoms) Helium, He_____________
d. 20 protons Calcium, Ca_____________
e. 0 neutrons Hydrogen, H_____________
12. At a minimum, what information must you have to determine the identity of an element? # of P+
A
A typical isotopic symbol takes this form: Z X
Where: X = element symbol; A = mass number [# of protons (p) + # neutrons (n)];
.
Z = atomic number [# of protons]; N = # of neutrons; A – Z = N
13. Fill in the missing items in the table below.
isotopic
symbol
Name
symbol
Z
A
#p
#e
#n
sodium
Na
11
23
11
11
12
23
11
Na
chlorine
Cl
17
35
17
17
18
35
17
Cl
potassium
K
19
39
19
19
20
39
19
K
symbol
Z
A
#p
#e
#n
phosphorus
P
15
31
15
15
16
iron
Fe
26
56
26
26
30
56
26
iodine
I
53
127
53
53
74
127
53
Name
symbol
Z
A
#p
#e
#n
isotopic
symbol
silver
Ag
47
108
47
47
61
108
47
Ag
krypton
Kr
36
84
36
36
48
84
36
Kr
tungsten
W
74
184
74
74
110
184
74
W
Name
isotopic
symbol
31
15
P
Fe
I
14. In a neutral atom, # Protons = # Electrons: True or False?
15. Thallium has two isotopes: thallium-203 and thallium-205. Thallium's atomic number is 81, and its atomic
mass is 204.38 amu. Which statement about the thallium isotopes is true?
a. There is more thallium-203 in nature
c. Thallium-205 atoms have fewer neutrons
b. Atoms of both isotopes have 81 protons
d. The mass of the most common Tl atom = 204.38 amu.
16. Atoms consist of: (check all that apply)
Protons
Neutrons
Molecules
Electrons
17. Which of these descriptions is incorrect?
Proton: positive charge, in nucleus, mass of = 1 amu
Electron: negative charge, mass of = 0 amu, in nucleus
Neutron: mass of = 1 amu, no charge
18. The atom that has atomic mass of 12 has ___6____________ protons.
19. What do you call an atom that is positively or negatively charged because it gained or lost one or more
electrons? Ion
20. The valence electron(s) is/are the outer most electron(s) in an atom.
21. The center of an atom is called the: nucleus
22. In an atom, the electrons form a cloud around the nucleus.
23. Objects that are electrically neutral become negatively charged when they gain electrons.
24. In an element with a neutral charge, the atomic number is equal to the number of p+ & e‒.
25. _____________ are particles with no charge.
Protons
Neutrons
Electrons
26. _____________ are negatively charged particles.
Protons
Neutrons
Electrons
27. _____________ are positively charged particles.
Protons
Neutrons
Electrons
28. The atom has the following parts
ions, protons, electrons
protons, electrons, neutrons
protons, electrons, molecules
elements, neutron protons
29. What charge do protons carry?
Positive
30. Is an atom the smallest particle of matter?
True
Negative
Neutral
False
31. Determine the average atomic mass of this mixture of naturally occurring isotopes of Barium.
Isotope
N.A.%
amu
Ba - 130
0.106%
0.1378
Ba - 132
0.101%
0.13332
Ba - 134
2.417%
3.23878
Ba - 135
6.592%
8.8992
Ba - 136
7.854%
10.68144
Ba - 137
11.23%
15.3851
Ba - 138
71.7%
98.946
Sum = 137.4216
32. Some possible sources of experimental error are: Inaccurate measurements; flawed methodology; poor
experimental design; careless practices; inadequate or inferior tools; unforeseen circumstances or
occurrences.