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Study Guide
Chemistry Test #5 - ANSWERS
Learning Goals for Unit #5:
 To identify key info about elements including:

Classification and state of matter at room temp

Family names

Valence electrons

Tendencies to lose, gain or share electrons

Special properties and whether or not they are found free in nature
 To explain how reactivity changes within a group - most reactive vs least reactive
 To define atomic radius and the factors that influence it
 To define electronegativity, electron affinity and ionization energy and…
 To identify the trends throughout the periodic table
 To explain relationship to atomic radius and classification of element
 To define ions and differentiate between ions and atoms
 To identify how ionic radius is different from atomic radius for a given element
1) Who is credited with producing the first periodic table?
Dimitri Mendeleev
2) Who is credited with discovering the correlation of periodicity with atomic number rather than
mass?
Moseley
3) Why are the alkali metals more reactive than the Group 13 metals? Use key terms.
Alkali metals have a larger radii, and lower ionization energies so easier to lose valence electron.
4) Which of the following elements are found free (elemental) in nature? P, Mg, K, S, Al, C, Br
Sulfur, carbon
5) Which family of elements is used in bulbs and lighted signs? Why?
Noble gases because they don’t react.
6) What is special about the valence electrons (the ones that are involved in bonding) of the transition
metals?
They are present in more than one shell leading to more than one oxidation state (different charges)
7) What do the metals in the Actinide series have in common? What special property do iron, cobalt
and nickel share?
Actinide – all are radioactive; iron, cobalt and nickel all produce a magnetic field
8) How is the design of the periodic table reflective of periodic law?
Periodic law says when elements are arranged in order of increasing atomic numbe, their physical and
chemical properties show a periodic trend. The grouping and number order of table reflects this.
9) What is the impact of nuclear charge and shielding on atomic radius?
As nuclear charge increases, without change in shielding, radius gets smaller because more protons and
electrons to attract. When shielding increases, valence electrons are further away so radius increases.
10) How does atomic radius influence electronegativity and ionization energy? What impact does that
have on reactivity of metals vs non-metals?
Larger radius means lower ionization energy and electronegativity. When radius gets larger, metals
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become more reactive. When radius gets smaller, non-metals become more reactive.
Study Guide
Chemistry Test #5 - ANSWERS
Directions: Match the appropriate definition with each key term
H
1. Metal
a)
Form ions by gaining electrons
L
2. Electronegativity
b)
Group 17 elements
I
3. Atomic radius
c)
Horizontal rows in periodic table
K
4. Anion
d)
d-block elements
M
5. Alkali metals
e)
Elements that do not react
J
6. Ionization energy
f)
A
7. Non-metal
g)
Atom that has lost or gained electrons and become
a charged particle
Vertical columns in periodic table
O
8. Cation
h)
B
9. Halogens
i)
N
10. Valence electrons
j)
C
11. Periods
k)
Energy required to remove an electron from an
atom
Negatively charged ion
G
12. Groups
l)
The ability of an atom to attract an electron
E
13. Noble gases
m) Group 1 elements
D
14. Transition metal
n)
Electrons in the outermost energy level
F
15. ion
o)
Formed when atoms LOSE electrons
Elements that are conductors, are bendable and
have luster
The size of the atom
1) Which class of elements will LOSE electrons during bonding? Explain why based on ionization
energy and/or electronegativity.
Metals will LOSE because they have a LOW ionization energy so easy to LOSE.
2) Which class of elements will GAIN electrons during bonding? Explain why based on ionization energy
and/or electronegativity.
Non-Metals will GAIN because they have a HIGH electronegativity so easy to ATTRACT.
3) For each group in the s and p blocks, identify the number of valence electrons:
Group #
Valence e
1
2
13
14
15
16
17
18
1
2
3
4
5
6
7
8
2
Study Guide
Chemistry Test #5 - ANSWERS
Trends-Atomic size, Shielding, Ionization Energy, Electron Affinity
1. Circle the one from each pair that would be the larger in size:
(A) F atom or O atom
(B) Ba atom or Ra atom
(C) Hf atom or Ti atom
(D) Cs ion or Ba ion
(E) Al ion or Al atom
(F) Po ion or At ion
2. Circle the element that has more shielding:
(A) B or In
(B) Mg or S or neither
(C) Tl or Y
(D) Cl or I
(E) Ar or Xe
(F) Ca or Ga or neither
3. Circle the element with the greater first ionization energy (IE):
(A) Pb or Sn
(B) B or C
(C) Ba or At
(D) Lr or Ra
(E) Cs or V
(F) Si or Ag
4. Circle the element with the greater electron affinity (EA):
(A) F or Cl
(B) Sr or Rb
(C) Os or Co
(D) Am or Eu
(E) Pb or Sn
(F) Ba or At
5. Circle the element with the lower electronegativity (EN):
(A) C or N
(B) Na or K
(C) Ta or Cu
(D) Pd or Mo
(D) Lr or Ra
(E) Cs or V
1) What is the difference between electron affinity and ionization energy?
Electron affinity has to do with gaining electrons and ionization energy has to do with losing electrons.
2) Why does oxygen have a higher ionization energy than selenium?
While oxygen and selenium both have 6 valence electrons, oxygen has a smaller radius so those
electrons are held more tightly which means more energy required for them to be removed.
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Study Guide
Chemistry Test #5 - ANSWERS
Use the periodic table below to answer the questions below it.
G
H
1) Between B and C, the highest electronegativity level?
G
2) Highest ionization energy
3) Between C and G, the largest atomic radius
4) Most reactive metal
C
C
H
5) Between B and E, the smallest atomic radius
6) Lowest electron affinity
E
H
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