Transcript Chapter 4: The Periodic Table

Chapter 4: The
Periodic Table
pg 123 #1-15, pg 131 #1-8, pg 142
#1-14, pg 148 #1-11
Pg 123 #1-15
1. State the periodic law.
The physical and chemical properties of the elements
are periodic functions of their atomic numbers.
2. What do elements in a period have in
common? Elements in a group?
Elements in a period have the same core-electron
configuration. Elements within a group have the same
outer electron configuration, and they also share
common properties.
Pg 123 #1-15 (cont.)
3. What contribution did Moseley make to
the development of the periodic table?
Moseley realized that the X-ray spectra of the elements
correlated with the atomic number of the elements and
not the atomic mass. When the elements were arranged
according to atomic number, the discrepancies in
Mendeleev’s periodic table disappeared.
Pg 123 #1-15 (cont.)
4. Write the atomic numbers and symbols
for each of the following elements.
a. silver 47 Ag
g. palladium 46 Pd
b. gold 79 Au
h. radon 86 Rn
c. mercury 80 Hg
i. radium 88 Ra
d. copper 29 Cu
e. zinc 30 Zn
f. platinum 78 Pt
Pg 123 #1-15 (cont.)
5. Which element in item 4 has the
greatest atomic mass? The least atomic
mass?
Greatest: Radium; Least: Copper
Pg 123 #1-15 (cont.)
6. Round the atomic masses for each
element listed in item 4 to the
hundredths place.
a. silver 107.87
f. platinum 195.08
b. gold 196.97
g. palladium 106.42
c. mercury 200.59 h. radon 222.02
d. copper 63.55
i. radium 226.03
e. zinc 65.39
Pg 123 #1-15 (cont.)
7. What is the name of the elements
located between the metals and
nonmetals in the periodic table?
semiconductors
9. Which elements are considered the
most stable? Why?
Noble gases; each noble gas has a filled octet.
Pg 123 #1-15 (cont.)
10. What is produced when halogens
combine with alkali metals?
salt
11. Why do groups of main-block elements
display similar chemical behaviors?
All of the elements in a group have the same outer-level
electron configuration.
Pg 123 #1-15 (cont.)
12. What do you expect the electron
configuration of element 112 to be?
7s25f146d10
13. Explain what the transition metals have
in common with respect to their electron
configurations?
The outermost electrons in transition metals are in s
orbitals and d orbitals, specifically, ns and (n – 1)d
orbitals, which are close in energy. A few have no s
electrons.
Pg 123 #1-15 (cont.)
14. What features do the halogens have in
common? The noble gases?
The halogens are reactive and combine with metals to form
salts. By gaining one electron, they achieve a stable octet and
become -1 ions. Noble gases are unreactive and have stable
octets of s and p electrons in the outer energy level.
15. Why is hydrogen placed in a group by itself?
Hydrogen has only 1 proton and 1 electron, and its behavior
does not match that of any of the groups of elements.
Pg 131 #1-8
1. What is the difference between a metal
and a nonmetal?
A metal is a good conductor of electricity, while a
nonmetal is not.
2. Why is copper used in electrical wiring?
Would gold or aluminum be a better
choice? Explain.
Copper is used in electrical wiring because it is an
excellent conductor of electricity, resists corrosion, and
is inexpensive.
Pg 131 #1-8 (cont.)
3. Define what is meant by malleability and
ductility.
Ductility is the capacity to be squeezed out into a wire.
Malleability is the capacity to be hammered or pressed
into sheets.
4. Identify the one property that all metals
share.
Electrical conductivity
Pg 131 #1-8 (cont.)
5. How is an alloy made?
Alloys can be made by melting metals together.
Sometimes non-metals are included.
6. What are crystals?
A crystal is a form of matter in which the molecules, ions,
or atoms of a crystal are arranged in an orderly geometric
pattern that repeats in 3 dimensions.
Pg 131 #1-8 (cont.)
7. Explain the difference in the conduction
bands of metals, nonmetals, and
semiconductors.
In metals, the conduction bands are low in energy, and
electrons are easily excited into those bands. In
semiconductors, the conduction bands are of higher
energy, so more energy is required to excite electrons
into those bands. Therefore, semiconductors are less
conducive than metals. In nonmetals, the conduction
bands are very high in energy, so it is very difficult to
excite electrons into them. Therefore, nonmetals are poor
conductors.
Pg 131 #1-8 (cont.)
8. Which electrons form the bonds that
bind atoms of an element together in a
crystal?
The outer electrons
Pg 142 #1-14
1. Why is it difficult to measure the size of
an atom?
Atoms are very small, and there is no definite boundary
to the electron cloud.
2. What does the term atomic radius
mean?
Atomic radius means “bond radius,” half the distance
between the nuclei of bonded atoms.
Pg 142 #1-14 (cont.)
3. What is the difference between bond
radius and van der Waals radius?
Van der Waals radius is half the distance between the
adjacent unbonded atoms.
4. What is ionization energy?
Ionization energy is the amount of energy needed to
remove an electron from an atom.
Pg 142 #1-14 (cont.)
5. What periodic trends exist for ionization
energy? What exceptions exist in these
trends?
Ionization energy generally increases from left to right
across a period and decreases from top to bottom in a
group. Group 2 and Group 15 elements have higher
ionization energies than the trend would indicate.
Pg 142 #1-14 (cont.)
6. What is electron affinity? How is it
different from ionization energy?
Electron affinity is the energy given off when an electron
is added to an atom. Electron affinity involves adding an
electron to an atom rather than taking one away.
7. What periodic trends exist for electron
affinity?
Electron affinities generally increase (in negative value)
across a period and decrease (in negative value) moving
down through a group.
Pg 142 #1-14 (cont.)
8. What trends are evident in atomic size
as you proceed down a group of
elements? How do each of these trends
progress as you move across a period?
Atomic size increases, ionization energy decreases, and
electron affinity decreases from top to bottom in a group.
Atomic size decreases, ionization energy increases, and
electron affinity increases from left to right across a
period.
Pg 142 #1-14 (cont.)
9. Define the term electron shielding.
Electron shielding occurs when underlying levels of
electrons reduce the attraction of the nucleus for the
outermost electrons.
10. What effect does electron shielding
have on atomic size? on ionization
energy? on electron affinity?
Electron shielding increases atomic size, decreases
ionization energy, and decreases electron affinity.
Pg 142 #1-14 (cont.)
11. What happens when an atom gains an
extra electron?
The atom becomes a negatively charged ion.
12. The periodicity of melting and boiling
points in Period 6 is the result of the
addition of electrons to which orbitals?
Electrons are added to 6s, 5d, and 6p orbitals.
Pg 142 #1-14 (cont.)
13. When an atom loses an electron, what
is its charge? What do you think
happens to the size of the atom?
The ion formed has a +1 charge. The atom becomes
smaller.
14. When an atom gains an electron, what
is its charge? What do you think
happens to its size?
The ion formed has a -1 charge. The atom becomes
larger.
Pg 148 #1-11
1. Define the term naturally occurring
element. Where are these elements
located in the periodic table?
Naturally occurring elements are those that can be
found in the universe. With few exceptions, the naturally
occurring elements are found in the first six periods of
the periodic table.
2. How and where were the naturally
occurring elements created?
They are produced by fusion reactions in stars.
Pg 148 #1-11 (cont.)
3. What element is the building block for all
other natural elements?
hydrogen
4. What is a synthetic element?
A synthetic element is made by the bombardment of
another element with neutrons, protons, or other atomic
nuclei.
Pg 148 #1-11 (cont.)
5. What is a nuclear reaction?
A nuclear reaction causes changes to the number of
protons and neutrons in an atom’s nucleus. The nucleus
usually transmutes to a different element.
6. What is transmutation?
The process by which on nucleus changes into another
by radioactive disintegration or bombardment with other
particles.
Pg 148 #1-11 (cont.)
7. In the first observed transmutation,
nitrogen was bombarded with alpha
particles to produce a hydrogen nucleus.
The other product was an ion of which
element?
oxygen-17
Pg 148 #1-11 (cont.)
8. How do scientists use cyclotrons to
create synthetic elements?
The cyclotron accelerates charged particles to high
energies. The particles are allowed to collide with existing
nuclei, changing them to other nuclei.
9. How are superheavy elements
prepared?
By bombarding nuclei of heavy elements with heavy ions
from accelerates to cause a nuclear reaction to form an
element with an atomic number greater than 106.
Pg 148 #1-11 (cont.)
10. What do scientists mean by the term
island of stability with respect to
superheavy synthetic elements?
Nuclei of atomic number 114 may be stable if they can be
produced.
11. What synthetic element was discovered
in 1982?
Meitnerium