Name:______Period:______Date:______

Ms. Randall/Mr. Palermo

Unit 2: Atomic Theory

Practice Packet

A.Atomic Structure Worksheet
**Assume all are neutral atoms!
Fill in the blanks in the following worksheet. Please keep in mind that the isotope represented by each space may NOT be the most common isotope or the one closest in atomic mass to the value on the periodic table.
Atomic symbol / Atomic number / Protons / Neutrons / Electrons / Mass number
C / 8
12 / 24
31 / 40
40 / 89
30 / 35
42 / 98
W / 183
105 / 71
95 / 243
Cr / 27
83 / 209
90 / 142
Md / 259
Se / 80
40 / 51

Notice there are two different atoms of zirconium (Zr) listed. They have drastically different mass numbers. What are these two considered to be in relation to one another?

B.Atomic Theory- Neutral Atoms and their subatomic parts

How many protons, neutrons, and electrons are present in the following neutral atoms?

vanadiumpotassium

nitrogenplatinum

argonhelium

What is the name of the element that has neutral atoms that contain?

5 protons16 electrons

______

17 protons32 electrons

______

25 protons1 electron

______

82 protons8 electrons

______

92 protons2 electrons

______

C.Complete the following chart: (assume the overall charge on all

atoms = 0….except the last one!)

Element / Symbol / Atomic Number / # of Protons / # of Neutrons / Mass Number (amu) / # of Electrons
Hydrogen / 1
He / 4
Na / 12
Potassium / 39
20 / 20
26 / 30
Rb / 86
Carbon / 6
Xenon / 131
16 / 15
At / 126
14 / 7
Copper / 64
Ne / 10
23 / 27
Lithium Ion / Li+ / 3

D. P, n, e of ions

Write the full chemical symbol for the ion with:

1)12 protons and 10 electrons:

2)74 protons and 68 electrons:

3)95 protons and 89 electrons:

4)33 protons and 36 electrons:

Determine the number of p, n, e for the following ions:

Cu2+Li+O2-

p =

n =

e =

Cl-Al3+I7+

E. Fill in the chart below

# protons / # electrons / # neutrons / Atomic # / Mass #
Lithium1+ / 3 / 4
Phosphorus3- / 18 / 31
Vanadium0 / 23 / 51
Krypton0 / 48 / 36
Barium4+ / 56 / 137
Uranium5- / 97 / 146

F. Fill in the chart below.

ATOM or ION? / PROTONS / NEUTRONS / ELECTRONS / MASS NUMBER / NUCLEAR CHARGE
Al+3
37Cl
23Na+1
He
15O-2
14C
C
Au+3
U
222Rn
Cu+1
Cu+2

Question: Which of the above atoms are isotopes of one another? Explain how you know this.

G.Complete the following table:

Substance / Atomic # / Mass # / Protons / Electrons / Neutrons
64Cu+2
8 / 17 / 10
32 / 32 / 41
14C
30 / 28 / 35
3Li+1
N
24 / 17 / 28
18
S+2

H. For the following atoms/ions determine the number of protons, neutrons, electrons, mass number, and nuclear charge.

ATOM or ION? / PROTONS / NEUTRONS / ELECTRONS / MASS NUMBER / NUCLEAR CHARGE
15N
Cu+2
8B+3
17O
F-1
206Pb
208Pb
Ag+1
Zn+2
Mg
S-2

Question: Which of the above atoms are isotopes of one another? Explain how you know this.

I. Calculate the atomic mass of each of the following isotopes. SHOW ALLWORK.

ElementMassPercent Abundance

1) copper-6362.9396 amu69.17%

copper-6564.9278 amu30.83%

2)uranium-235235.0439 amu0.72%

uranium-238238.0510 amu99.28%

3)hydrogen-11.0078 amu99.985%

hydrogen-22.0140 amu0.015%

4)element Q-88 amu10.0%

element Q-99 amu20.0%

element Q-1010 amu70.0%

J. Weighted Averages HW

SHOW ALL WORK*You can round the masses given to you or use them as given – just be consistent!

1)Element X exists in three isotopic forms. The isotopic mixture consists of 10.0% 10X, 20.0% 11X, and 70.0% 12X. What is the average atomic mass of this element?

2)Element Y exists in three isotopic forms. The Isotopic mixture consists of 15.0% 21X, 65.0% 22X, and 20.0% 23X. That is the average atomic mass of this element?

3)A mystery element occurs in nature as two isotopes. Isotope A has a mass of 10.0130 amu and its abundance is 19.9%; Isotope B has a mass of 11.0093 amu and its abundance is 80.1%. From this data, calculate the atomic mass of the element and show all work. Lastly, identify the element.

4)A mystery element occurs in nature as two isotopes. Isotope A has a mass of 62.939598 amu and its abundance is 69.17%; Isotope B has a mass of 64.927793 amu and its abundance is 30.83%. From this data, calculate the atomic mass of the element and show all work. Lastly, identify the element.

5)A mystery element occurs in nature as three isotopes. Isotope A has a mass of 15.994915 amu and its abundance is 99.762%; Isotope B has a mass of 16.999132 amu and its abundance is 0.0380%; Isotope C has a mass of 17.999160 amu and its abundance is 0.2000%. From this data, calculate the atomic mass of the element and show all work. Lastly, identify the element.

K.Isotopes and Average Atomic Mass

Example: A sample of cesium is 75% 133Cs, 20% 132Cs, and 5% 134Cs. What is the average atomic mass?

Determine the average atomic mass of the following mixtures of isotopes.

  1. 80% 127I, 17% 126I, 3% 128I
  1. 50% 197Au, 50% 198Au
  1. 15% 55Fe, 85% 56Fe
  1. 99% 1H, 0.8% 2H, 0.2% 3H
  1. 95% 14N, 3% 15N, 2% 16N

6. 98% 12C, 2% 14C

L.Construct Bohr diagrams for the following:

Na
electron configuration ______ / F
electron configuration ______
O
electron configuration ______ / Li+
electron configuration ______
Cl-
electron configuration ______ / Ne
electron configuration ______

M. Draw Lewis Dot Diagrams for the following:

NC

Li+He

OB

SKr

Se2-Ca+2

N. Electron Configuration Worksheet

For the questions 1-10, assume all atoms are neutral. Based on the electron configurations given, determine the identity of the element and whether it is in the ground or excited state.

Electron Configuration / Identity / Ground/Excited
  1. 2-8-1

  1. 2-8-16-3

  1. 2-8-2

  1. 2-7-8

  1. 1-3

  1. 2-8-6

  1. -18-32-18-4

  1. -18-32-17-3

  1. 2-7

  1. 1-8

Give an electron configuration for the following:

  1. Sulfur in its ground state.

  1. Helium in an excited state.

  1. When atoms of an element are emitting a certain wavelength (or color) of light, it means that

a)the atoms have gained energy and electrons have jumped to an excited state.

b)the atoms have gained energy and electrons have fallen back to the ground state.

c)the atoms have lost energy and electrons have fallen back to the ground state.

d)the atoms have lost energy and electrons have jumped to an excited state.

Use the emissions spectra results below to answer questions 14 and 15:

Gas A

Gas B

Gas C

Gas D

Unknown Gas

  1. According to these experimental spectra results, the unknown gas is a mixture of which gases? ______
  2. Each line on the visible light spectrum for the gases above represents

a)electrons jumping to the same excited state or energy level.

b)electrons falling back down to their ground state from the same energy level.

c)electrons jumping to multiple excited states or energy levels.

d)electrons falling back down to their ground state from multiple energy levels.

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