# Holt Chemistry

## Educators

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Problem 1

What group of elements do Ca, Be, and Mg
belong to?

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Problem 2

What group of elements easily gains one
valence electron?

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Problem 3

What category do most of the elements of
the periodic table fall under?

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Problem 4

What is the term for the energy released
when an atom gains an electron?

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Problem 5

What are elements $90-103$ called?

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Problem 6

Give an example of a nuclear reaction.
Describe the process by which it takes place.

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Problem 7

What are elements in the first group of the
periodic table called?

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Problem 8

What atomic property affects periodic
trends down a group in the periodic table?

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Problem 9

What two atomic properties have an
increasing trend as you move across a
period?

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Problem 10

Write a paragraph describing in
elements are created. Discuss what modification has to be made to the
equipment in order to synthesize super-heavy elements.

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Problem 11

Which group of elements has very high
ionization energies and very low electron
affinities?

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Problem 12

How many valence electrons does a fluorine
atom have?

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Problem 13

Give an example of an alloy.

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Problem 14

How was Moseley's arrangement of the
elements in the periodic table different
from Mendeleev's?

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Problem 15

What did the gaps on Mendeleev's periodic
table represent?

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Problem 16

Why was Mendeleev's periodic table
accepted by most chemists?

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Problem 17

What determines the horizontal arrangement of the periodic table?

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Problem 18

Why is barium, Ba, placed in Group 2 and
in Period 6$?$

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Problem 19

Why is hydrogen in a class by itself?

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Problem 20

All halogens are highly reactive. What
causes these elements to have similar
chemical behavior?

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Problem 21

What property do the noble gases share?
How do the electron configurations of the
noble gases give them this shared property?

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Problem 22

How do the electron configurations of the
transition metals differ from those of the
metals in Groups 1 and 2$?$

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Problem 23

Why is carbon, a nonmetal element, added
to iron to make nails?

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Problem 24

If an element breaks when it is struck with a
hammer, could it be a metal? Explain.

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Problem 25

Why are the lanthanides and actinides
placed at the bottom of the periodic table?

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Problem 26

Explain why the main-group elements are
also known as representative elements.

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Problem 27

What periodic trends exist for ionization
energy? How does this trend relate to
different energy levels?

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Problem 28

Why don't chemists define atomic radius as
the radius of the electron cloud that surrounds a nucleus?

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Problem 29

How does the periodic trend of atomic

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Problem 30

What happens to electron affinity as you
move across a period beginning with Group
1? Why do these values change as they do?

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Problem 31

Identify which trend diagram below

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Problem 32

What periodic trends exist for electronegativity? Explain the factors involved.

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Problem 33

Why are the melting and boiling points of
mercury almost the lowest of the elements
in its period?

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Problem 34

How does nuclear fusion generate energy?

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Problem 35

What happens in the nucleus of an atom
when a transmutation takes place?

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Problem 36

Why are technetium, promethium, and
neptunium considered natural elements

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Problem 37

Why must a synchrotron be used to create
a superheavy element?

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Problem 38

What role did supernovae play in creating
the natural elements?

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Problem 39

What two elements make up most of the
matter in a star?

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Problem 40

Without looking at the periodic table,
identify the period and group in which
each of the following elements is located.
$$\begin{array}{l}{\text { a. }[\mathrm{Rn}] 7 s^{1}} \\ {\text { b. }[\mathrm{Ar}] 4 s^{2}} \\ {\text { c. }[\mathrm{Ne}] 3 s^{2} 3 p^{6}}\end{array}$$

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Problem 41

Which of the following ions has the electron
configuration of a noble gas: $\mathrm{Ca}^{+}$ or $\mathrm{Cl}^{-} ?$
(Hint: Write the electron configuration for
each ion.)

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Problem 42

When 578 $\mathrm{kJ} / \mathrm{mol}$ of energy is supplied, Al
loses one valence electron. Write the
electron configuration of the ion that forms.

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Problem 43

Name three periodic trends you encounter

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Problem 44

How do the electron configurations of the
lanthanide and actinide elements differ from
the electron configurations of the other
transition metals?

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Problem 45

Use the periodic table to describe the chemical properties of the following elements:
$$\begin{array}{l}{\text { a. iodine, I }} \\ {\text { b. krypton, Kr }} \\ {\text { c. rubidium, Rb }}\end{array}$$

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Problem 46

The electron configuration of argon differs
from those of chlorine and potassium by
one electron each. Compare the reactivity of
these three elements, and relate them to
their electron configurations.

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Problem 47

What trends were first used to classify the
elements? What trends were discovered
after the elements were classified in the
periodic table?

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Problem 48

Among the main-group elements, what is
the relationship between group number and
the number of valence electrons among
group members?

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Problem 49

Consider two main-group elements, $\mathrm{A}$ and
B. Element A has an ionization energy of
419 $\mathrm{kJ} / \mathrm{mol} .$ Element $\mathrm{B}$ has an ionization
energy of 1000 $\mathrm{kJ} / \mathrm{mol} .$ Which element is
more likely to form a cation?

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Problem 50

Argon differs from both chlorine and potassium by one proton each. Compare the electron configurations of these three elements
to explain the reactivity of these elements.

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Problem 51

While at an amusement park, you inhale
helium from a balloon to make your voice
higher pitched. A friend says that helium
reacts with and tightens the vocal cords to make your voice have the higher pitch.
Could he be correct? Why or why not?

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Problem 52

In his periodic table, Mendeleev placed Be,
Mg, Zn, and Cd in one group and Ca, Sr, Ba,
and Pb in another group. Examine the electron configurations of these elements, and
explain why Mendeleev grouped the elements this way.

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Problem 53

The atomic number of yttrium, which follows strontium in the periodic table, exceeds
the atomic number of strontium by one.
Barium is 18 atomic numbers after strontium but it falls directly beneath strontium in the periodic table. Does strontium share
more properties with yttrium or barium?

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Problem 54

Examine the following diagram.
Explain why the structure shown on the
right was drawn to have a smaller radius
than the structure on the left.

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Problem 55

Select an alloy. You can choose one mentioned in this book or find another one by
checking the library or the Internet. Obtain information on how the alloy is made.
Obtain information on how the alloy is
used for practical purposes.

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Problem 56

Construct a model of a synchrotron. Check
the library and Internet for information
about synchrotrons. You may want to contact a synchrotron facility directly to
find out what is currently being done in
the field of synthetic elements.

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Problem 57

In many labeled foods, the mineral content
is stated in terms of the mass of the element,
in a stated quantity of food. Examine the
product labels of the foods you eat.
Determine which elements are represented in your food and what function each element serves in the body. Make a poster of
foods that are good sources of minerals that
you need.

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Problem 58

Use the following terms to create a concept
map: atomic number, atoms, electrons, periodic table, and protons. Study the graph below, and answer the questions that follow.
For help in interpreting graphs, see Appendix $B$ , "Study Skills for Chemistry."

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Problem 59

What relationship is represented in the
graph shown?

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Problem 60

What do the numbers on the $y$ -axis
represent?

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Problem 61

In every Period, which Group contains
the element with the greatest atomic

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Problem 62

Why is the axis representing group
number drawn the way it is in going
from Group 2 to Group 13$?$

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Problem 63

Which period shows the greatest change

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Problem 64

Notice that the points plotted for the
elements in Periods 5 and 6 of Group 2
overlap. What does this overlap indicate?

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Problem 65

Graphing Atomic Radius Vs. Atomic Number

The graphing calculator can run a program
that graphs data such as atomic radius versus atomic number. Graphing the data
within the different periods will allow you
to discover trends.

Go to Appendix $C$ . If you are using a TI-83
data sets and run the application as directed.
Press the APPS key on your calculator, then choose the application CHEMAPPS. Press 8
then highlight ALL on the screen, press 1 ,
data into your calculator. Quit the application, and then run the program RADIUS. For $\mathrm{L}_{1},$ press 2 $\mathrm{nd}$ and $\mathrm{LIST},$ and choose AINUM. For $\mathrm{L}_{2},$ press 2 $\mathrm{nd}$ and $\mathrm{LIST}$ and choose
have an atomic radius of 20 $\mathrm{pm} ?$ Explain.