Download BM 1 - answer key - Annapolis High School

1
Chemistry first quarter Review
Outcome
Demonstrate
experimental design
Demonstrate
experimental design
Name_____________________________________________________Pd______
Sample Question
1. Which instruments are used during a lab investigation for measuring mass, volume and
height for the given object
2.Use the table to find the mass of NaCl:
Evaporating Dish + lid
Evaporating Dish + lid + HCl
Evaporating Dish + lid + NaCl
38.5g
43.6g
42.7g
Answer
Mass- electronic scale, volume – graduated cylinder, height - ruler
Mass of NaCl = 42.7 g -38.5g = 4.2 g
1.75 L x 1000ml = 1750 mL
1L
How many milliliters are in 1.75L? ( use factor label method)
How many Kilograms are in 250 grams?
Distinguish between
elements and
compounds
Explain the
characteristics of
chemical changes
Compare the early
theories of the atom.
Identify subatomic
particles of the atom.
Describe the
discovery of the
nucleus by
explaining
Rutherford's
experiment
3. Which of the following is a compound and can be chemically decomposed?
A. Na
E.MgO
B. NaCl
C. CCl4
D. Cl
4. What are four clues that indicate that a chemical change has taken place?
5. Give the scientist who is responsible for each model
__1. an indivisible sphere with uniform density
__2. positively charged atom embedded with electrons
__3. a small, dense, positively core with most of the atom empty space
__4. small, dense nucleus consisting of protons and neutrons with electrons in levels outside
the nucleus
6. Which of these contains most of the atom’s mass
7. Complete the following chart
Subatomic location relative charge
Particle
mass
e
n
p
How will you describe a proton? Write three points.
8. What three things did Rutherford observe in his gold foil experiment and what did they
tell him about the atom?
250g x 1Kg
= .25 Kg
1000 g
The correct answer is B, C and E. Elements joined together in a chemical
formula make a compound. Na and Cl are elements. They can be
chemically decomposed
1. formation of a precipitant, 2. formation of a gas, 3. change in color(or
other physical properties) 4. production of heat or loss of heat These
indicate that a new substance has been formed with different physical and
chemical properties
1.
2.
3.
4.
Dalton
Thomson
Rutherford
Bohr (modern)
Nucleous
Positively charged protons and neutral neutrons are located in the nucleus
of the atom. This core contains most of the mass of the atom and is very
small, therefore very dense. Electrons (negatively charged) are found
outside the nucleus in specific energy levels that can be determined. It
would take 2000 electrons to equal the mass of one proton or one
neutron.
Protons are positively charged , heavy subatomic particles inside the
nucleus
1. Most of the alpha particles pass straight through the atom. This told R
that they hit nothing. Most of the atom is empty space.
2. A few of the alpha particles (which have a positive charge) were
deflected. This told R that the alpha particles passed close to something
with a positive charge. The nucleus is positive.
3. A very few alpha particles bounced straight back. This told R that the
alpha particles his something that is very massive and very small (very
dense). His conclusion is that the atom has a small, dense, positively
charged core. We call this the nucleus. Most of the atom is empty space.
2
Compare atomic
sizes to macroscopic
sizes by using
scientific notation
Identify atomic
number, mass
number and isotopes
given the number of
protons, neutrons
and electrons.
Multiply and write the answer in their proper significant digits
6.2x 7.81
8.22x 6.0
6.2 x 7.81 = 48.422 = 48 (round off to 2 significant digits)
8.22 x 6.0= 49.32 = 49 ( round off to 2 sig. fic.)
10. a. Determine the number of electrons, protons and neutrons in the following isotopes.
10. a. Element
Lithium-7
26
13 Al
Li-7
3
4
3
26
13
13
13
13
Al
protons
neutrons
electrons
10 .b.Explain what do you mean by an isotope? Give example.
11. What do you mean by a neutral atom?
Write atomic
particles in the
correct notation and
calculate a weighted
average of isotopes
of an element..
12. Explain why 1224Mg and 1225Mg are classified as isotopes.
13. Lithium – 7 has an atomic number of 3 and an atomic mass of 7 because
A. it has 3 protons and 7 neutrons
B. it has 3 protons and 4 neutrons
C. it has 7 protons and 3 neutrons
D. it has 4 protons and 3 neutrons
10. two atoms are isotopes of each other when they are the same element
(same number of protons) but have different numbers of neutrons
(different atomic mass).
11. Neutral atom has same number of protons and electrons.
12. Isotopes are the same element because they have the same number of
protons, but they have different numbers of neutrons and therefore
different atomic masses.
14. Choose which pair below are isotopes of each other
13. B is the correct answer
24
12 Mg
A.
25
Mg
12
14. A is the correct answer.
B.
24
12
24
Mg
C. 1327Al
13
13
Al
27
Si
15.a.
80
35Br
# of P
D. 13 27Al
24
12 Mg
X
# of ( P + N)
b. 28Ni58
15. Write a symbol like those in the question above and name the element.
a) An isotope with 35 protons and 45 neutrons
d) An isotope with 28 electrons and 30 neutrons
Write atomic
particles in the
correct notation
16. Use this representation of an atom to tell the number of protons, neutrons and electrons.
14
6 C
A.
B.
C.
D.
6 protons, 14 neutrons, 6 electrons
6 protons, 14 neutrons, 4 electrons
6 protons, 14 neutrons, 8 electrons
6 protons, 8 neutrons,6 electrons
D is the correct answer
The subscript gives number of protons.
The superscript gives protons + neutrons.
The number of electrons in a neutral atom is the same as the number of
protons.
3
Describe the
structure of an
electron cloud.
17. Write three laws of electron distribution
Afbau,s Principle , Pauli,s exclusive Principle and Hund,s Rule
18(a). Which one is the right ground state orbital diagram for sulfur?
a.      _
Describe the modern
views of the atom by
comparing Bohr's
model to the
Quantum
Mechanical model.
1s
2s
2p
3s
 _ _
B is the correct answer
3p
B      _  _ _
1s
2s
2p
3s
C      _
1s
2s
2p
3s
D      _
1s
2s
2p
3s
3p
  _
Carbon .  
3p
 _ _
3p
1s
Nitrogen

2s
2p
 
1s
 __
2s

 
2p
18.(b) Draw orbital notation for carbon and Nitrogen
Compare an orbit to
an electron cloud by
describing the
location of the
electron
Explain how the
colors of light are
related to changes in
electron energies by
analyzing atomic
emission spectra.
19. How many electrons can accommodate in an orbital?
2 electrons can accommodate in an orbital
20. Tell if energy is absorbed or released when
A. an electron leaps from a lower energy state to a higher energy state
B.
an electron falls back from a higher energy level to a lower energy level
A. energy is absorbed
B. energy is released
21. How is light be produced by exciting electrons with energy?
When an electron absorbs energy of certain wavelengths, it leaps to a
higher energy state and quickly falls back to the ground state, giving off
energy we sometimes see as light. The color of light given off is
determined by the amount of energy given off by the electron as it falls to
the ground state..
4
Describe early
attempts to organize
chemical elements
and develop the
periodic law by
constructing a
periodic table.
Differentiate
between metals,
nonmetals and
metalloids
22. Mendeleev is given credit for the development of the PT. What is the major difference
in the table he developed and the modern periodic table?
Mendeleev said that the properties of the elements are periodic if
elements are arranged by increasing atomic mass. The use of mass was
incorrect as Mendeleev found with the discovery of reversed pairs.
Modern periodic law says the properties are periodic (and elements are in
the same column if they have similar properties) if the elements are
arranged by increasing atomic number.
23. Why did Mendeleev leave gaps in his periodic table?
Which of the following pairs have similar properties
K and Ca
K and Cs
K and Sr
K and Br
When Mendeleev was arranging the periodic table, many elements had
not been discovered. Mendeleev left gaps for these missing elements and
predicted many of their properties from their location on the periodic
table.
K and Cs as they belong to same group on PT
24. List some properties of metals and nonmetals.
Metals- shiny, conduct heat and electricity, malleable, ductile, react with
hydrochloric acid
Nonmetals – dull, do not conduct heat and electricity, brittle, do not react
with HCl
25. Design a lab to determine the properties of metals and nonmetals. Include Outcome,
material list, step by step procedure, data table and conclusion
Choose known metals and nonmetals and check the properties above.
Include purpose, materials, and data table.
Illustrate the number
of valence electrons
using electron dot
structure.
26. An element is located on the right of the periodic table, is dull, brittle, and yellow in
color and does not conduct electricity. The element is a
A. metal
B. nonmetal
C. metalloid
D. cannot be determined from the description
27. Which of the following in group 16 will have the strongest metallic properties
A. O
B.Se
C.Te
D.Po
28. For the given atomic numbers , identify which element is metal, nonmetal , or metalloid
a.16
b. 10
c.3
d 14
Metals are shiny, malleable, conduct electricity and heat, are located to
the left of the stair step line, and have few electrons that they hold on to
loosely.
Nonmetals are dull, do not conduct electricity or heat, are brittle, are
located to the right of the stair step line, and have 5 or more electrons in
the outer level which they hold onto tightly. Metalloids are located on
the stair step line (Al and Po are exceptions) and have some properties of
metals, some properties of nonmetals.
26. B
27. The correct answer is D.
28. a. nonmetal
b. noble gases , nonmetal
c. metal
d. metalliod
.
5
Identify and describe
groups and families
on the periodic table.
Explain periodic
trends by analyzing
the characteristics of
elements on the
periodic table.
29. Name the following parts of the periodic table.
A. Column 1 (IA)
B. Column 2 (IIA)
C. Column 17 (VIIA)
D. Column 18 (VIIIA)
E. Columns 3-12 (IB – VIIIB)
F. Elements 57 – 71
G. Elements 89 – 103
H. Vertical columns
I.
Horizontal rows.
30. Why does ionization energy increase as atomic radius decreases?
A. a weaker nucleus means electrons can get farther from the nucleus and the most
loosely held electron is easier to remove.
B. A stronger nucleus means electrons can get farther from the nucleus and the most
loosely held electron is easier to remove.
C. A weaker nucleus means electrons are held tighter to the nucleus and the most
loosely held electron is harder to remove.
D. A stronger nucleus means electrons are held tighter to the nucleus and the most
loosely held electron is harder to remove.
31. Explain the reason for the following trends
A. decreasing radius size and increasing ionization energy across a period or series
B.
increasing radius size and decreasing ionization energy down a group or family
32. What do you mean by an ion and what is the relationship between atomic radius and
ionic radius?
33. What is the difference in electron activity for metallic properties and for nonmetallic
properties?
A. metals lose electrons; nonmetals gain electrons
B. nonmetals lose electrons; metals gain electrons
C. metals react to get 6 electrons in their outer level
D. nonmetals react to get 6 electrons in their outer level
Describe cations and
anions by analyzing
their formation.
34. When Ca becomes a ion
A. loses 1 electron to have a +1 charge
B. loses 2 electrons to have a + 2 charge
C. gains 1 electron to have a -1 charge
D. gains 2 electrons to have a -2 charge
A. alkali metals
B. alkaline earth metals
C. halogens
D. noble gases
E. transition elements
F. Lanthanide series
G. Actinide series
H. groups/families
I. periods.
30. D is the correct answer.
Radius and IE both depend on nuclear strength. The nucleus gets
stronger left to right on the PT because more protons pull the electrons
tighter. The nucleus gets weaker from top to bottom on the PT because
the inner level electrons shield some of the nucleus ‘ pull from the outer
level electrons.
For metals, chemical reactivity is greatest at the lower left of the PT
because metals react by losing electrons and the weaker atoms lose
electrons more readily.
For nonmetals, chemical reactivity is greatest at the upper right of the PT
because nonmetals react by gaining electrons and the stronger nuclei gain
electrons more readily.
31. A. The nucleus grows stronger with added protons, pulling the
electrons tighter and decreasing radius. It is harder to remove an electron
from the more tightly held electrons.
B. As you go down a column on the PT, more protons and electrons are
added. These electrons are added in increasing energy levels. The
electrons in the inner levels shield some of the nucleus’ pull from the
outer level electrons. These electrons are able to travel farther from the
nucleus. It is easier to remove one of these less tightly held electrons.
32. Atom after losing or gaining electrons becomes an ion. After losing
electrons atom becomes Cation and have a smaller radius as compare to
its atom. After gaining electrons atom becomes an anion and has a
larger radius as compare to its atom.
33. The correct answer is A. Metals have low electronegativity (weak
nuclei) and give up electrons to nonmetals with their high
electronegativity (strong nuclei).
34. B