Download EOCT Physical Science Atomic Theory

EOCT Physical Science Atomic Theory (EOCT_PhySci_Atomic_Theory)
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1. The noble gases are unlikely to react with other elements
because the outer electron shell of most noble gases
A. has two electrons.
B. has four electrons.
C. is incomplete.
D. is full.
2. Why do noble gases almost never form chemical bonds?
A. It is difficult for gases to form bonds.
B. They have filled outer valence shells.
C. They have very small atomic radii.
D. They are very rare.
3. The formation of water droplets on the inside of a
window pane during a cold night is an example of
A. dehydration.
B. sublimation.
C. condensation.
D. fermentation.
4. Different isotopes indicate that an element will have
different numbers of
A. atoms.
B. protons.
C. neutrons.
D. electrons.
5.
Of the particles listed, which is the smallest unit of water that has all of
the properties of water?
A. proton
B. atom
C. molecule
D. mixture
6.One property of an electron is
A. a net charge of 0.
B. a charge of +1.
C. a charge of -1.
D. an atomic mass of -1.
7. Water has a natural tendency to dissociate,
producing a small number of hydroxide ions (OH-) and
A. positive hydrogen ions.
B. negative hydrogen ions.
C. positive oxygen ions.
D. negative oxygen ions.
8.Which of the following most accurately defines chemical energy?
A. energy stored as attraction between protons and electrons
B. energy stored in bonds between atoms
C. energy stored as accumulations or deficiencies of electrons
D. energy stored in the nuclei of more than one atom
9.Oxygen and hydrogen form water in a
A. homogeneous mixture.
B. hydrophobic reaction.
C. chemical reaction.
D. spontaneous condensation.
10.Sodium becomes positively charged when it combines with chlorine because sodium
A. loses one electron.
B. gains one electron.
C. forms a covalent bond.
D. has more electrons than protons.
11.The nucleus of a hydrogen atom is formed by
A. a proton.
B. an electron.
C. a proton and an ion.
D. a neutron and an electron.
12. The nucleus of the most common isotope of hydrogen is formed by
A. a single proton.
B. a single neutron.
C. one proton and one electron.
D. one neutron and one proton.
13. By using electrolysis, salt can be separated into sodium metal
and chlorine gas, and water can be separated into hydrogen gas
and oxygen gas. No further physical or chemical techniques can
be used to change any of these components because they are
A. ions.
B. atoms.
C. elements.
D. compounds.
14. Atoms of N and P each have 5 electrons in their outer shells. What else must these
two elements have in common?
A. They must be in the same period.
B. They must have the same atomic mass.
C. They must have the same total number of electron shells.
D. They must be found in the same group in the periodic table.
15.A chemical change occurs when a substance
A. changes state.
B. gains or loses electrons.
C. reaches its boiling point.
D. is ground into a powder.
16. Which of the following is a chemical change?
A. Water is decomposed into hydrogen gas and oxygen gas.
B. Water droplets collect on the outside of a glass filled with ice.
C. A boiling pot of water produces steam.
D. Water is frozen into ice.
17. Use the picture below to answer this question.
A candle is placed beneath a small glass dish that holds scented oil. The heat from
the candle warms the oil, and black residue forms above the flame on the underside
of the dish. This residue is the result of a
A. physical change in the state of the wax.
B. chemical change that causes oxygen to change state.
C. physical change that causes the oil to be absorbed by the dish.
D. chemical change that produces carbon from the wax.
18. Isotopes of an element have
A. a different number of protons and neutrons.
B. the same number of protons and neutrons, but no electrons.
C. the same number of protons but a different number of neutrons.
D. the same number of neutrons but a different number of protons.
19.
Which of the following characterizes a radioactive element?
A. an unfilled inner electron shell
B. the ability to gain 4 electrons in the outer shell
C. the loss of alpha or beta particles from the nucleus
D. an equal number of neutrons and protons in the nucleus
20. The process in which a liquid changes to gas is called
A. condensation.
B. evaporation.
C. freezing.
D. precipitation.
21. The process which changes water into a vapor or gas is called
A. condensation.
B. evaporation.
C. precipitation.
D. sublimation.
22. A star gives off heat and light from the nuclear fusion reaction that takes place inside.
What change happens during the nuclear reaction?
A. Nitrogen is changed to hydrogen.
B. Helium is changed to hydrogen.
C. Hydrogen is changed to nitrogen.
D. Hydrogen is changed to helium.
23.
Which of the following provides evidence that an egg white undergoes a chemical
change when it is heated?
A. Its mass decreases.
B. It is in a liquid state.
C. Its temperature rises steadily.
D. Its color permanently changes.
24.
Which of the following gives an atom's mass number?
A. number of neutrons
B. number of neutrons + number of protons
C. number of protons + number of electrons
D. number of protons + number of neutrons + number of electrons
25.
When referring to the element phosphorus on the periodic table, the number 15 is
the
A. energy level.
B. atomic weight.
C. atomic number.
D. number of atoms.
26.
Hydrogen and helium are members of
A. group 1.
B. group 2.
C. period 1.
D. period 18.
27.
What type of change does gaseous oxygen undergo when it is liquified?
A. chemical
B. ionization
C. ozonation
D. physical
28.
Mixing an acidic solution with marble chips causes bubbles of carbon dioxide gas to
form. Which of the following accurately describes this change?
A. phase change
B. physical change
C. chemical change
D. radioactive change
29.
Which of the following accurately compares melting and sublimation?
A. Only one is a physical change.
B. Only one involves a loss of mass.
C. Both are chemical changes.
D. Both are phase changes of a solid.
30.
Which of the following do protons and electrons have in common?
A. their location in an atom
B. the sign of their charge
C. the size of their charge
D. their mass
31.
Three atoms combine to form a single unit of a larger substance. This is a
A. nucleus.
B. mixture.
C. solution.
D. molecule.
32.
The smallest particle that maintains the chemical properties of a compound is
A. a molecule.
B. an isotope.
C. a proton.
D. an atom.
33.
An atom containing only a single proton and no electrons is
A. an anion.
B. a noble gas.
C. a form of hydrogen.
D. a radioactive metal.
34. The atomic weight of an element most nearly reflects the atom's total number of
A. protons and neutrons.
B. protons and electrons.
C. electrons and neutrons.
D. protons only.
35. Atoms of the same element with different numbers of neutrons are called
A. acids.
B. bases.
C. gases.
D. isotopes.
36. The mass of an electron is
A. equal to the proton mass plus the neutron mass.
B. the smallest of the three major particles.
C. the same as the mass of the proton.
D. the same as the mass of the atom.
37. What is the main problem in developing nuclear fusion as an efficient source of
energy?
A. The fuel needed is too expensive at this time.
B. Dangerous gamma and neutron rays are given off.
C. The energy produced is equal to the energy needed to create the reaction.
D. Extremely high temperatures and pressures are needed, requiring a container of great
strength.
38.
Which subatomic particles are negatively charged?
A. protons only
B. neutrons only
C. electrons only
D. both neutrons and electrons
39. Which atomic particles are charged?
A. only electrons
B. electrons and neutrons
C. electrons and protons
D. electrons, neutrons, and protons
40. The chemical activity of an atom depends mostly on its
A. protons only.
B. neutrons only.
C. electrons.
D. protons and neutrons.
41. As Cyndie mixed two liquids together, she observed the resulting mixture was hotter
than either of the two liquids before they were mixed. What had caused this increase in
temperature?
A. Electricity had been generated.
B. A physical change had occurred.
C. A chemical reaction had occurred.
D. Hydrogen bonds in the water had been broken.
42.
In 1897, the British physicist J.J. Thomson was researching electrical conduction in
gases. He discovered that cathode rays consisted of negatively charged particles.
Thomson is generally regarded as the discoverer of the
A. quark.
B. atomic nucleus.
C. proton.
D. electron.
43. What is the name for the time required to change a part of a radioactive element to a
stable element?
A. half life
B. time span
C. development period
D. effective chemical life
44. Isotopes of elements are identified by differences in their
A. mass number.
B. electron count.
C. atomic number.
D. negative charges.
45.
The total number of electrons that can be held in the second energy level of an atom
is
A. 2.
B. 6.
C. 8.
D. 10.
46.
The Mg2+, a magnesium ion, has how many electrons?
A. 2
B. 6
C. 8
D. 10
47.
Carolyn was walking on the sidewalk in front of a store and had to step over a
melting ice cream cone. What type of change was the ice cream undergoing?
A. chemical
B. molecular
C. organic
D. phase
48.
Which of the following is a physical change?
A. combustion
B. electrolysis
C. fermentation
D. sublimation
49.
What chemical change takes place when an iron nail rusts?
A. Iron atoms and salt molecules bond.
B. Iron atoms and water molecules bond.
C. Iron atoms and oxygen molecules bond.
D. Water erodes oxide ions from the surface.
50.
Which is a property of an electron?
A. It has the same mass as a proton.
B. It is found in the nucleus of an atom.
C. It has the same charge as a proton.
D. It has much less mass than a neutron.
51. Which of the following are transferred or shared when two atoms react
chemically?
A. protons
B. neutrons
C. electrons
D. photons
52. In a restaurant kitchen, lamps are used to keep food warm. Which type of
electromagnetic radiation do the lamps emit that is primarily responsible for
keeping the food warm?
A. gamma
B. infrared
C. ultraviolet
D. visible
53. As you move from left to right across a row of elements in the periodic table,
what happens to the number of neutrons in a typical atom?
A. It stays the same.
B. It increases.
C. It decreases.
D. It decreases until you reach the middle and then it increases.
54. A solid cube was put into a cylinder containing four liquids with different densities as
shown below.
The cube fell quickly through layer A, fell slowly through layer B, and stopped upon
reaching layer C. The density of the cube most likely lies between
A. 1.00 and 1.50 g/cm3.
B. 1.51 and 3.50 g/cm3.
C. 3.51 and 6.00 g/cm3.
D. 6.00 and 9.00 g/cm3.
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55. The illustration below shows two atoms of a fictitious element (M) forming a
diatomic molecule.
What type of bonding occurs between these two atoms?
A. covalent
B. ionic
C. nuclear
D. polar
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Massachusetts Department of Education.
56. Which of the following describes a particle that contains 36 electrons, 49 neutrons,
and 38 protons?
A. an ion with a charge of 2B. an ion with a charge of 2+
C. an atom with a mass of 38 amu
D. an atom with a mass of 49 amu
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Massachusetts Department of Education.
57. The illustration below shows a hot-air balloon. The pilot can change the altitude of
the hot-air balloon by changing the temperature of the gas inside the balloon. When the
gas is heated, the balloon rises.
Which of the following best explains this phenomenon?
A. Heating the gas reduces its pressure.
B. Heating the gas decreases its density.
C. Heating the gas decreases its molecular motion.
D. Heating the gas reduces the frequency of the gas molecules' collisions.
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Massachusetts Department of Education.
58. Block X and Block Y have the same mass. Both blocks are placed into a container of
pure water. Block X floats in the water, and Block Y sinks to the bottom of the container.
Which of the following statements is an accurate conclusion from this demonstration?
A. Block Y is heavier than Block X.
B. Block Y is less dense than Block X.
C. Block Y has a smaller volume than Block X.
D. Block Y would float if more water were added.
This online assessment item contains material that has been released to the public by the
Massachusetts Department of Education.
59. Which of the following occurs when a rigid container of gas is heated?
A. The pressure inside the container increases.
B. The pressure inside the container decreases.
C. The pressure inside the container stays the same.
D. The pressure inside the container changes the composition of the gas.
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Massachusetts Department of Education.
60. Which of the following is the same for both hydrogen and potassium?
A. atomic mass
B. total mass of neutrons
C. number of valence electrons
D. number of filled energy levels
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Massachusetts Department of Education.
61. The bar graph below represents four elements and their relative atomic numbers.
What would be the most likely positioning of these unknown elements in the periodic
table?
A.
B.
C.
D.
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Massachusetts Department of Education.
62. The illustration below shows the lab equipment set up by a student to find the melting
and freezing points for naphthalene, a chemical used as an insect repellent.
A small sample of solid naphthalene (C10H8) is placed in the capillary tube attached to the
thermometer and is heated in the water bath until the white solid melts. The student then
turns the heat off and observes the sample as it cools, recording the temperature at regular
intervals.
What will most likely happen to the colorless liquid naphthalene when the temperature
reaches the freezing point of naphthalene?
A. The naphthalene will change into a yellow liquid.
B. The naphthalene will crystallize into a white solid.
C. The naphthalene will begin to form small bubbles.
D. The naphthalene will disappear from the capillary tube.
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Massachusetts Department of Education.
63. Perfume sprayed from a bottle spreads more easily in a warm room of 25°C than in a
cool room of 15°C. Which of the following correctly compares perfume molecules at
25°C to those at 15°C?
A. At 25°C, they have more mass.
B. At 25°C, they are moving faster.
C. At 25°C, they have less kinetic energy.
D. At 25°C, they are decreasing in volume.
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Massachusetts Department of Education.
64.
The atomic mass number of an element equals the
A. number of protons or electrons.
B. sum of the protons plus electrons.
C. number of protons or electrons.
D. sum of the protons plus neutrons.
65.
What do we definitely know about an atom of magnesium, the element following sodium
in the periodic table?
A. Magnesium is more reactive than sodium.
B. Magnesium contains more protons than sodium.
C. Sodium has more valence electrons than magnesium.
D. Magnesium contains more protons and neutrons than sodium.
66.
Compare the elements in the halogen family. Which statement is true regarding a
progression from fluorine to iodine?
A. The elements progressively change phase from gas to liquid to solid.
B. The elements form progressively higher charged ions.
C. The elements become progressively less reactive.
D. The elements decrease in density.
67.
Which of these elements would you expect to be solid at room temperature?
A. N
B. O
C. Ca
D. Rn
68.
As you move from left to right across the periodic table, characteristics of the elements
change as well. Which is the correct sequence, moving from left to right?
A. metal - metalloid - nonmetal
B. metal - nonmetal - metalloid
C. metalloid - metal - nonmetal
D. nonmetal - metalloid - metal
69.
Locate the following four elements in the periodic table.
Fe, Hg, Sn, Xe
Which element has the most valence electrons?
A. Fe
B. Hg
C. Sn
D. Xe
70.
Which statement best describes the elements in the Noble gas family?
A. Noble gases are highly flammable.
B. Noble gases combine readily with reactive metals.
C. Noble gases react with oxygen to form gaseous molecules in the ozone.
D. Noble gases are nonreactive and have a valence number of "0".
71.
Which of these statements is true about sodium (Na)?
A. Sodium is an inert gas and does not combine readily with other elements.
B. Sodium is a reactive nonmetal and combines readily with other nonmetals.
C. Sodium is less reactive than magnesium (mG0 when combining with nonmetals like
oxygen (O).
D. Sodium is less reactive than potassium (K) when combining with nonmetals like
oxygen (O).
72.
Which of these statements is true?
A. Metals tend to lose electrons and form positive ions.
B. Nonmetals tend to lose electrons and form positive ions.
C. Metalloids do not form compounds readily.
D. Gases share electrons and form positive ions.
73.
A group of physical science students made some observations about a metal sample
during lab.
Shiny reddish-brown color
Mass – 25.18 g
Volume – 2.81 cm3
The students were working with four metals. They included:
magnesium - density 1.74 g/cm3
aluminum - density 2.7 g/cm3
copper - density 8.96 g/cm3
silver - density 10.5 g/cm3
The metal they identified must be
A. aluminum.
B. copper.
C. magnesium.
D. silver.
74.
Several students are trying to determine if an aluminum cube will float in water, density
0.999 g / cm3. If the length of each side of the cube is 3.0 cm and the mass is 72.9 grams,
what should happen when the cube is placed in water?
A. It will sink.
B. It will float.
C. It will float for a short period of time and then sink.
D. It will float with 3/4 of the cube's volume below the water's surface.
75.
As a substance changes from a liquid to a solid
A. the average kinetic energy decreases.
B. the average kinetic energy increases.
C. the potential energy decreases.
D. the temperature increases.
76.
As you view the illustrations from left to right, from one state of matter to another, which
of these statements is correct?
A. The average kinetic energy of the molecules decreases.
B. The average kinetic energy of the molecules increases.
C. The attractive force between the molecules increases.
D. The average temperature decreases.
77.
If the volume of a hot air balloon remains constant, what happens as the temperature of
the air inside the balloon increases?
A. The pressure inside the balloon decreases.
B. The pressure inside the balloon increases.
C. The kinetic energy of the air inside decreases
D. The attractive force between the air particles inside increases.
78.
Which of these types of radiation is LEAST dangerous to living cells?
A. alpha particles
B. beta particles
C. theta particles
D. gamma waves
79.
The half-life of bismuth is 5 days. How much of a 100 gram sample will remain after 20
days?
A. 50 grams
B. 12.5 grams
C. 6.25 grams
D. 0 grams
80.
A radioactive isotope has a half-life of 2.0 years. The fraction of a pure sample of the
isotope that will have decayed in 6.0 years is
A. 1/8.
B. 1/3.
C. 3/4.
D. 7/8.
81.
Order these types of nuclear radiation from LOWEST to HIGHEST energy.
A. alpha particles, beta particles, gamma rays, UV-rays
B. alpha particles, beta particles, UV-rays, gamma rays
C. gamma rays, UV-rays, alpha particles, beta particles
D. UV-rays, gamma rays, alpha particles, beta particles
82.
The illustration represents what type of nuclear reaction?
A. alpha decay
B. beta decay
C. fission
D. fusion
83.
Today, some power plants use nuclear fission to convert nuclear energy into electrical
energy. Which is a potential risk associated nuclear power plants?
A. decreased dependency on oil
B. thermal pollution of rivers and streams
C. increased carbon dioxide levels in our atmosphere
D. reduced sulfur dioxide emissions into the atmosphere
84.
An atom of chlorine forms an ionic bond when combined with an atom potassium.
However, an atom of chlorine forms a covalent bond with combined with an atom of
carbon. Which statement correctly describes an electron of chlorine in these two different
bonds?
A. Electrons spend more time closer to the chlorine in the ionic bond.
B. Electrons spend more time closer to the carbon in the covalent bond.
C. Electrons spend equal time around the chlorine and potassium in the ionic bond.
D. Electrons spend equal time around the chlorine and carbon in the covalent bond.
85.
Isotopes of an element differ in the number of
A. valence electrons.
B. electrons in the nucleus.
C. protons in the nucleus.
D. neutrons in the nucleus.
86.
The illustration above represents a molecule of methane. Which of the following
statements is true concerning the chemical bonds of methane?
A. Electrons are transferred.
B. Electrons are shared.
C. The bonds occur between a metal and a nonmetal.
D. The bonds are ionic.
87.
An electrically neutral atom of sodium has 11 protons. Based on this information, what
else can we say about an atom of sodium?
A. Sodium has 11 protons and 11 neutrons.
B. Sodium has 11 electrons.
C. Sodium has 11 neutrons.
D. The atomic mass number is 11.
88.
What subatomic particle is located in the nucleus of an atom?
A. both electrons and isotopes
B. both neutrons and positrons
C. both neutrons and electrons
D. both protons and neutrons
89. Elements from which two groups in the periodic table would most likely combine
with each other to form an ionic compound?
A. 1 and 2
B. 16 and 17
C. 1 and 17
D. 17 and 18
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90. An ice-skating rink has tubes under its floor to freeze the water. Salt water is
cooled well below the freezing point of water and pumped through the tubes to
freeze the water in the rink. Why can the salt water be cooled so low without
freezing?
A. Salt has a very low freezing point.
B. Adding salt to water lowers its freezing point.
C. Movement of the salt water through the tubes keeps it in the liquid state.
D. The salt water is constantly absorbing energy from its surroundings.
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91. In chemical compounds, covalent bonds form when —
A. the electronegativity difference between two atoms is very large.
B. electrons are completely transferred between two metals.
C. pairs of electrons are shared between two nonmetal atoms.
D. two nonmetal ions are attracted to each other by opposite charges.
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92. Three elements, X, Y, and Z, have consecutive increasing atomic numbers. If
element X is a noble gas, what will be the symbol for the ion of element Z in its
compounds?
A.
B.
C.
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93. Atoms of the same element must —
A. contain the same number of neutrons.
B. have the same mass number.
C. contain the same number of protons.
D. have equal numbers of protons and neutrons.
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94. Water molecules have the greatest kinetic energy in —
A. ice at 0° C
B. water at 373° K.
C. water at 98° C
D. steam at 150° C
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95. The alkali metals are located in which group of the periodic table?
A. 1
B. 2
C. 3
D. 4
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96.
Which of these elements has an atomic number of 14?
A. N
B. Al
C. Si
D. P
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97. A neutral atom of aluminum-27 contains —
A. 13 protons and 27 electrons.
B. 14 protons and 13 neutrons.
C. 13 electrons, 13 protons, and 14 neutrons.
D. 13 electrons, 14 protons, and 13 neutrons.
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98. Which of the following properties decreases from left to right across a period?
A. Atomic number
B. Electronegativity
C. Atomic radius
D. Ionization energy
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99.
The graph shows the pressure of an ideal gas as a function of its volume. According
to the graph, increasing the volume from 100 mL to 150 mL —
A. decreases the pressure by 80 kPa
B. decreases the pressure by 160 kPa
C. increases the pressure by 80 kPa
D. increases the pressure by 160 kPa
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100. Which of these belongs in the outermost shell (energy level) of an atom?
A. Electrons
B. Protons
C. Neutrons
D. Photons
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101.
Which represents an atom of calcium?
A. 1
B. 2
C. 3
D. 4
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102. A scientist has found the following isotope of oxygen:
How many neutrons are present in this isotope?
A. 8
B. 11
C. 19
D. 27
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103. According to Boyle's law, the relationship between the pressure and volume of
a gas at constant temperature is —
A. numerically equivalent.
B. inversely proportional.
C. positively correlated.
D. totally unrelated.
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Answer Key
1. D) is full.
2. B) They have filled outer valence shells.
3. C) condensation.
4. C) neutrons.
5. C) molecule
6. C) a charge of -1.
7. A) positive hydrogen ions.
8. B) energy stored in bonds between atoms
9. C) chemical reaction.
10. A) loses one electron.
11. A) a proton.
12. A) a single proton.
13. C) elements.
14. D) They must be found in the same group in the periodic table.
15. B) gains or loses electrons.
16. A) Water is decomposed into hydrogen gas and oxygen gas.
17. D) chemical change that produces carbon from the wax.
18. C) the same number of protons but a different number of neutrons.
19. C) the loss of alpha or beta particles from the nucleus
20. B) evaporation.
21. B) evaporation.
22. D) Hydrogen is changed to helium.
23. D) Its color permanently changes.
24. B) number of neutrons + number of protons
25. C) atomic number.
26. C) period 1.
27. D) physical
28. C) chemical change
29. D) Both are phase changes of a solid.
30. C) the size of their charge
31. D) molecule.
32. A) a molecule.
33. C) a form of hydrogen.
34. A) protons and neutrons.
35. D) isotopes.
36. B) the smallest of the three major particles.
37. D) Extremely high temperatures and pressures are needed, requiring a container of
great strength.
38. C) electrons only
39. C) electrons and protons
40. C) electrons.
41. C) A chemical reaction had occurred.
42. D) electron.
43. A) half life
44. A) mass number.
45. C) 8.
46. D) 10
47. D) phase
48. D) sublimation
49. C) Iron atoms and oxygen molecules bond.
50. D) It has much less mass than a neutron.
51. C) electrons
52. B) infrared
53. B) It increases.
54. C) 3.51 and 6.00 g/cm3.
55. A) covalent
56. B) an ion with a charge of 2+
57. B) Heating the gas decreases its density.
58. C) Block Y has a smaller volume than Block X.
59. A) The pressure inside the container increases.
60. C) number of valence electrons
61. D)
62. B) The naphthalene will crystallize into a white solid.
63. B) At 25°C, they are moving faster.
64. D) sum of the protons plus neutrons.
65. B) Magnesium contains more protons than sodium.
66. A) The elements progressively change phase from gas to liquid to solid.
67. C) Ca
68. A) metal - metalloid - nonmetal
69. D) Xe
70. D) Noble gases are nonreactive and have a valence number of "0".
71. D) Sodium is less reactive than potassium (K) when combining with nonmetals like
oxygen (O).
72. A) Metals tend to lose electrons and form positive ions.
73. B) copper.
74. A) It will sink.
75. A) the average kinetic energy decreases.
76. B) The average kinetic energy of the molecules increases.
77. B) The pressure inside the balloon increases.
78. A) alpha particles
79. C) 6.25 grams
80. D) 7/8.
81. B) alpha particles, beta particles, UV-rays, gamma rays
82. D) fusion
83. B) thermal pollution of rivers and streams
84. A) Electrons spend more time closer to the chlorine in the ionic bond.
85. D) neutrons in the nucleus.
86. B) Electrons are shared.
87. B) Sodium has 11 electrons.
88. D) both protons and neutrons
89. C) 1 and 17
90. B) Adding salt to water lowers its freezing point.
91. C) pairs of electrons are shared between two nonmetal atoms.
92.
93. C) contain the same number of protons.
94. D) steam at 150° C
95. A) 1
96. C) Si
97. C) 13 electrons, 13 protons, and 14 neutrons.
98. C) Atomic radius
99. A) decreases the pressure by 80 kPa
100. A) Electrons
101. A) 1
102. B) 11
103. B) inversely proportional.