Name_______________________
Period________
Test Review Honors Key
Unit 2: The Atom
1. If you run electricity through a tube filled with a gas, that gas would emit light.
a. What is going on with the electrons that causes this to happen?
When an electron is at ground state, it possesses the minimum energy needed to stay in motion and not get
sucked into the nucleus. When electrons absorb photons (packets or particles) carrying energy, they go from
ground state to an excited state, father away from the nucleus (sugar high). Eventually, the electrons want to
release photons carrying energy in the form of light to feel more comfortable and get closer to the nucleus.
2. What are the three foundational laws of chemistry? Be able to apply and give examples if required.
Law of Conservation of Mass – mass is neither created nor destroyed
Ex. 12g Carbon + 10 g Oxygen
 22 g Carbon Dioxide
Law of Definite Proportions – if only 1 compound can be made from the chemical combination of 2 elements,
then the percent by mass of each of these elements remains constant, regardless of sample size
Ex. NaCl
60.66% Cl and 39.34% Na
Law of Multiple Proportions – if more than 1 compound can be made from the chemical combination of 2
elements, than the elements must still combine in simple whole number ratios
Ex. CO versus CO2
1:2 ratio of oxygen
3. Show the orbital, electron, and noble gas and valence configuration for each of the following elements:
Orbital
Electron
1s22s22p63s23p64s23d7
Co:
1s22s22p63s23p64s23d104p65s24d105p66s24f145d7
Ir:
Se-2
1s22s22p63s23p64s23d104p6
Noble Gas
Valence
[Ar]4s23d7
4s2
[Xe]6s24f145d7
6s2
[Kr]
4s24p6
4. Below give the quantum numbers that describe the location of the indicated electron in the atom.
n
l
ml
ms
Co (The 6th electron)
2
1
0
+1/2
st
Ir (The 26 electron
3
2
-2
-1/2
Identify the elements whose last electron has the following 4 quantum numbers:
n=5
l=2
ml = -2
ms = + ½
La
n=5
l=3
ml = 1
ms = -1/2
Fm
5. What is the average atomic mass of an atom of zinc given that there are 5 isotopes of this element each with
a relative abundance as follows: Remember to show all work, label and use appropriate sig figs.
Isotopes
Zn-64
Zn-66
Zn-67
Zn-68
Zn-70
Relative Abundance
48.89%
27.81%
4.11%
18.57
0.62%
Atomic Mass
63.929
65.926
66.927
67.925
69.925
65.387 amu
6. How is an isotope different than an atom? How is an ion different that an atom? What subatomic particle
identifies that element?
An isotope is an atom with a different mass due to a different number of neutrons.
An ion is a charged particle due to the gain or loss of electrons in an atom.
The subatomic particle that identifies the element is the proton.
7. Complete the following chart:
# Protons
# Neutrons # Electrons
10
12
10
79
118
79
17
20
17
Mass #
22
197
37
Atomic #
10
79
17
8. Draw the shape of the s, p, and d orbitals.
Element Symbol
Ne-22
Au-197
Cl-37
Atomic Mass
20.18 amu
196.97 amu
35.45 amu
Draw the single s orbital overlapped with the
3 p orbitals.
9. Write the nuclear symbol and the hyphen notation for the isotope of antimony that has 53 neutrons.
104
Sb
Sb-104
10. Make sure you review the history of the development of the current atomic theory – including names,
contributions, scientific equipment used and in chronological order of development. Draw a picture of each
scientists atom.
Dalton:
JJ Thomson:
Rutherford:
Bohr:
11. Where are each of the following groups located on the periodic table? Give at least one unique property of
each of the following groups of elements?
Alkali Metals
Halogens
Metalloids
Alkaline Earth Metals
Noble Gases
Transition Metals
Alkali Metals- Group 1, most reactive metals on the periodic table. Form +1 ions, losing 1 electron to look like
a noble gas. Too reactive to exist in nature freely. Must be stored in mineral oil.
Alkaline Earth Metals – Group 2, not as reactive as alkali metals. Form +2 ions, losing 2 electrons to look like
a noble gas.
Halogens – Group 7, most reactive metals on the periodic table. Form -1 ions, gaining 1 electron to look like a
noble gas. Known as the salt formers, since they tend to bond with a metal to create a solid, ionic compound.
There is a solid, liquid and gas in this family.
Noble Gases- Group 8, the most stable elements on the periodic table due to a full valence shell. All elements
want to look like them. These gases are many times used for lighting purposes.
Metalloids – Located on the staircase of the periodic table. Possess properties of both metals and nonmetals.
Transition Metals – Located in the middle section of the periodic table. Contain the precious metals (Cu, Ag,
Pt, Au) and the magnetic elements (Co, Ni and Fe).
12. How did Demitri Mendeleev arrange the elements on the periodic table?
Increasing atomic mass
13. How did Henry Mosely arrange the elements on the period table? What is the periodic law based upon?
Increasing atomic number. The physical and chemical properties of the elements are functions of their atomic
numbers.
14. How is electron configuration reflected in the period table’s organization?
Each element represents 1 electron. The electron configuration pattern follows increasing atomic number.
15. Explain the trend in ionization energy based on the trend of atomic radii and why?
Ionization energy, the amount of energy needed to remove an electron from the valence shell of an atom,
increases across a period and decreases down a group.
Atomic radaii (size of the atom) decreases across a period and increases down a group.
These trends are opposite of one another. As the atom gets larger, it becomes easier for an electron to be
removed from its valence shell due to the shielding effect. As the atom gets smaller, the amount of energy
needed to remove an electron from the valence shell becomes greater due to an increase in nuclear charge. The
valence shell is located closer to the nucleus and opposites attract. The nucleus holds on tighter to the valence
electrons.
16. Explain the trend in atomic radii based on electron shielding and why?
As the atom gets larger going down a group due to the shielding effect. There are more energy levels and
electrons on these inner levels that shield the attraction of the positive nucleus to the negative electrons on the
outermost shell. The greater distance from the valence shell to the nucleus with the addition of energy levels
makes the size of the atom larger.
17. What is ionization energy? What element has the lowest ionization energy and why?
Ionization energy, the amount of energy needed to remove an electron from the valence shell of an atom,
increases across a period and decreases down a group. Francium is the element with the lowest ionization
energy on the periodic table because of it’s 1 valence electron being on the 7th energy level. It doesn’t take
much energy to remove this electron from the valence shell because of the shielding effect and great distance
away from the nucleus.
18. What is electronegativity? What element has the lowest electronegativity and why?
Electronegativity is the desire to gain or attract an electron. Francium has the lowest desire to attract an electron
to its valence shell. It would rather lose an electron to look like radon. It would be extremely hard for francium
to gain or attract an electron to it because of the shielding effect, and weak pull from the nucleus.
19. What happens to the radius of an atom when an electron is added to its outer shell and why?
When an electron is added to the outer shell of an atom to form an ion, the radius increases. There is more
repulsion occurring which forces the ion to get bigger.
20. What happens to the radius of an atom when an electron is removed from its outer shell and why?
When an electron is removed from the outer shell of an atom to form an ion, the radius decreases. There is less
repulsion occurring which forces the ion to get smaller.
21. What is the wavelength (in cm) of light that has a frequency of 5.66 x 1014 s-1? What color of light is this?
*Please see typing error in problem
 = 5.3 x 10-9 cm
530 nm is green light
22. If an electron absorbs blue light (421nm), how much energy did it absorb?
E = 4.7 x 1049 J
***Be sure to review the “Atom Quiz” and “Atom Quiz” study guide as well as all worksheets, labs and
powerpoints for more examples and sample problems to prepare you for the test.