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Chapter 6
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The Periodic Table
Class
SMALL-SCALE EXPERIMENT
A PERIODIC TABLE LOGIC PROBLEM
Small-Scale Experiment for text Section 6.3
OBJECTIVES
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Analyze properties and relationships of 26 elements.
Identify each element’s place in the periodic table based on these properties and relationships.
INTRODUCTION
When elements are arranged in the periodic table in order of increasing atomic number, there is a periodic repetition
of their physical and chemical properties. The way properties change from left to right across a period and from top
to bottom within a group are called periodic trends. Here is a summary of some periodic trends.
Atomic size can be expressed by a measurement called the atomic radius. Atomic radius is one half the distance
between the nuclei of two atoms of the same element when the atoms are joined. The atomic radius generally
increases from top to bottom within a group. The atomic radius generally decreases from left to right across a period.
Ionization energy is the energy required to remove an electron from an atom. This energy is measured when the
atom is in the gaseous state. The first ionization energy is the energy required to remove the first electron from an
atom. The second ionization energy is the energy required to remove an electron from a cation with a 1+ charge. The
third ionization energy is the energy required to remove an electron from a cation with a 2+ charge. The second
ionization energy for an element is always larger than the first ionization energy. The third ionization energy is
always larger than the second ionization energy. In general, first ionization energy decreases from top to bottom
within a group and increases from left to right across a period.
Electronegativity is the ability of an atom of an element to attract electrons when the atom is in a compound. In
general, electronegativity values decrease from top to bottom within a group and increase from left to right across a
period. Because noble gases do not tend to form compounds, electronegativity values for noble elements are usually
omitted from data tables.
Metals tend to have low first ionization energies and low electronegativity values. Nonmetals tend to have high
first ionization energies and high electronegativity values.
Experiment 9 A Periodic Table Logic Problem
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PURPOSE
In this experiment, you will use a series of clues to arrange a set of unknown elements in a periodic table. The elements
are the elements with atomic numbers 1–20 and 31–36. A letter of the alphabet is used to represent each unknown
element. The letter designation is not related to an element’s chemical symbol. Each clue refers to a property of an
element or a relationship an element has to other elements in the periodic table. Along with logic and knowledge of
properties, you will use periodic trends to solve the puzzle. When you are done, each element will be in its unique place
on the table. Good luck!
SAFETY
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Behave in a way that is consistent with a safe classroom.
EQUIPMENT
sharp pencil
EXPERIMENTAL PROCEDURE
Use the following periodic trend clues to place the elements in their proper places in the short form of the periodic table
provided.
A
Has one of the highest electronegativities on the table
B
Has one electron in a 3p orbital
C
Has five electrons in the fourth energy level
D
Forms the smallest 2 ion
E
Tends to gain one electron
F
Electronic configuration is 1s22s22p63s23p3
G Is the most electronegative element
H An ion of this element with a 2 charge has 18 electrons.
I
Its second ionization energy is large compared to its first ionization energy.
J
Its highest occupied energy level is full.
K This nonmetal is likely to form an ion with a 3 charge.
L
Has the highest first ionization energy in the table
M Has the smallest atomic radius in the third period
N
Is the smallest atom in its group
O The first element with an electron in the second energy level
P
The only nonmetal in a group with highly reactive metals
Q Has eight fewer protons than its “groupmate” H
R
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The most likely element of the ones included to lose an electron
Small-Scale Chemistry Laboratory Manual
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S
A metalloid in period 4
T
Its ionic radius is larger than its atomic radius.
U
The ion with a 2 charge that it forms has 18 electrons.
V
Atomic number is 34
Class
W Metalloid that forms an ion with a 3 charge
X
Has characteristics of both a metal and a nonmetal
Y
Has a lower first ionization energy than S
Z
Has a first ionization energy that is higher than T but lower than M
EXPERIMENTAL DATA
Using the clues given in the Experimental Procedure, place the letter of each element in its place on the following short
form of the periodic table.
Experiment 9 A Periodic Table Logic Problem
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QUESTIONS FOR ANALYSES
Use what you learned in this experiment to answer the following questions.
1. Which elemental clues contain sufficient information to place the element, using no other information?
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2. Excluding elements identified in your answer to Question 1, for which clues could you identify a group based solely
on an individual clue?
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3. Which elements were you able to place based on electronegativity?
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4. Which of the following properties increase from top to bottom within a group?
Which increase from left to right across a period?
a. first ionization energy
b. electronegativity
c. atomic radius
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NOW IT’S YOUR TURN!
1. Design your own periodic table logic problem based on the 26 elements with atomic numbers 1–20 and 31–36.
Name each element after your friends, sports teams, favorite movies, musical groups, colors, or anything you like.
Assign a symbol to each element and place it on the table. Devise and write one clue for each element that will lead
to its placement. For example, “Turquoise, Tu, is the second lightest noble gas.” Have a classmate solve your puzzle
and advise you about any problems he or she might encounter in solving it. Revise the logic problem according to
your classmate’s suggestions.
2. Search the Internet to find and solve other periodic logic problems or post your own!
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Small-Scale Chemistry Laboratory Manual