Hs Chemistry Practice Final
Practice final exam for the first semester of basic high school chemistry.
Questions and Answers
- 1.
Convert 57.03mm to meters
- A.
0.005703m
- B.
0.05703m
- C.
0.5703m
- D.
57,030.0m
Correct Answer
B. 0.05703mExplanation
To convert millimeters to meters, we divide the value in millimeters by 1000. In this case, 57.03mm divided by 1000 equals 0.05703m. Therefore, the correct answer is 0.05703m.Rate this question:
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- 2.
Convert 17.2°C to Kelvin
- A.
256.35 K
- B.
298.15 K
- C.
237.35 K
- D.
290.35 K
Correct Answer
D. 290.35 KExplanation
To convert Celsius to Kelvin, we add 273.15 to the Celsius value. In this case, adding 273.15 to 17.2 gives us 290.35. Therefore, the correct answer is 290.35 K.Rate this question:
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- 3.
Convert 0.00924kg to mg
- A.
9.240mg
- B.
92.40mg
- C.
924.0mg
- D.
9240mg
Correct Answer
D. 9240mgExplanation
To convert kilograms to milligrams, we need to multiply the given value by 1000 since there are 1000 milligrams in one kilogram. Therefore, 0.00924kg is equal to 9240mg.Rate this question:
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- 4.
Convert 375.12 K to °C
- A.
275.12°C
- B.
648.27°C
- C.
101.97°C
- D.
475.12°C
Correct Answer
C. 101.97°CExplanation
To convert Kelvin (K) to Celsius (°C), we need to subtract 273.15 from the given temperature. In this case, 375.12 K - 273.15 = 101.97°C. Therefore, the correct answer is 101.97°C.Rate this question:
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- 5.
You have a 25mL graduated cylinder and an unknown mass of Zinc. You fill the graduated cylinder with 10mL of water and drop the sample of Zinc in carefully. The water rises to 12mL. If the density of Zinc is 7.14 g/mL, what is the mass of the sample of Zinc used?
- A.
0.280g
- B.
14.3g
- C.
92.8g
- D.
107g
Correct Answer
B. 14.3gExplanation
The density of a substance is defined as its mass divided by its volume. In this case, the volume of water displaced by the zinc is 12mL - 10mL = 2mL. Using the density formula, we can calculate the mass of the zinc using the given density of 7.14 g/mL: mass = density x volume = 7.14 g/mL x 2 mL = 14.28 g. Rounding to the nearest tenth, the mass of the sample of zinc used is 14.3g.Rate this question:
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- 6.
Which of the following elements are transition metals? (You may select multiple answers)
- A.
Manganese (Mn)
- B.
Silicon (Si)
- C.
Strontium (Sr)
- D.
Gold (Au)
Correct Answer(s)
A. Manganese (Mn)
D. Gold (Au)Explanation
Manganese (Mn) and Gold (Au) are transition metals. Transition metals are elements that have partially filled d or f orbitals in their atomic structure. Manganese is a transition metal because it has partially filled d orbitals, specifically in the 3d subshell. Gold is also a transition metal because it has partially filled d orbitals in the 5d subshell. Silicon (Si) and Strontium (Sr) are not transition metals as they do not have partially filled d or f orbitals in their atomic structure.Rate this question:
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- 7.
Which of the following elements has the largest atomic radius?
- A.
Nitrogen (N)
- B.
Zinc (Zn)
- C.
Tungsten (W)
- D.
Radium (Ra)
Correct Answer
D. Radium (Ra)Explanation
Radium (Ra) has the largest atomic radius among the given elements. Atomic radius refers to the size of an atom, which is determined by the distance between the nucleus and the outermost electron shell. Radium has more electron shells and a larger number of electrons compared to the other elements listed. This results in a larger atomic radius for Radium.Rate this question:
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- 8.
Order the following elements in order of increasing ionization energy: Hg, Fr, Cl, F, As
- A.
F, Cl, As, Hg, Fr
- B.
Fr, Hg, As, Cl, F
- C.
As, F, Cl, Fr, Hg
- D.
Hg, Fr, Cl, F, As
Correct Answer
B. Fr, Hg, As, Cl, FExplanation
The ionization energy is the energy required to remove an electron from an atom or ion. Generally, ionization energy increases from left to right across a period and decreases from top to bottom within a group on the periodic table.
In this question, the elements are Fr (Francium), Hg (Mercury), As (Arsenic), Cl (Chlorine), and F (Fluorine). Francium is in the first period and the alkali metal group, so it has the lowest ionization energy. Mercury is a transition metal and has a higher ionization energy than Francium. Arsenic is a metalloid and has a higher ionization energy than Mercury. Chlorine is a nonmetal and has a higher ionization energy than Arsenic. Fluorine is the most electronegative element and has the highest ionization energy among the given elements. Therefore, the correct order of increasing ionization energy is Fr, Hg, As, Cl, F.Rate this question:
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- 9.
True or False: Lithium (Li) is an alkaline earth metal.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Lithium (Li) is not an alkaline earth metal. It is a chemical element that belongs to the alkali metal group. Alkaline earth metals are a different group of elements in the periodic table, which includes elements like calcium, magnesium, and barium.Rate this question:
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- 10.
Which of the following elements are Lanthanoids? (You may select multiple answers)
- A.
Lead (Pb)
- B.
Einsteinium (Es)
- C.
Potassium (K)
- D.
Terbium (Tb)
Correct Answer
D. Terbium (Tb)Explanation
Terbium (Tb) is the correct answer because it is one of the elements in the Lanthanoid series. Lanthanoids are a group of elements that have similar chemical properties and are part of the f-block in the periodic table. Lead (Pb) and Potassium (K) are not Lanthanoids, while Einsteinium (Es) is a transuranic element and not part of the Lanthanoid series.Rate this question:
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- 11.
Which element has a mass number of 32?
- A.
Sulfur (S)
- B.
Germanium (Ge)
- C.
Chlorine (Cl)
- D.
Arsenic (As)
Correct Answer
A. Sulfur (S)Explanation
Sulfur (S) has a mass number of 32. The mass number is the sum of the number of protons and neutrons in an atom's nucleus. Sulfur has 16 protons and 16 neutrons, giving it a mass number of 32. Germanium (Ge) has a mass number of 72, chlorine (Cl) has a mass number of 35, and arsenic (As) has a mass number of 75. Therefore, the correct answer is Sulfur (S).Rate this question:
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- 12.
How many neutrons are present in a Carbon-14 atom?
- A.
4 neutrons
- B.
6 neutrons
- C.
8 neutrons
- D.
10 neutrons
Correct Answer
C. 8 neutronsExplanation
Carbon-14 is an isotope of carbon, meaning it has the same number of protons but a different number of neutrons. The atomic number of carbon is 6, indicating it has 6 protons. Since the atomic mass of carbon-14 is 14, subtracting the number of protons gives the number of neutrons. Therefore, a carbon-14 atom has 8 neutrons.Rate this question:
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- 13.
An atom of which element has 12 protons, 12 neutrons, and 12 electrons?
- A.
Carbon (C)
- B.
Nitrogen (N)
- C.
Magnesium (Mg)
- D.
Sodium (Na)
Correct Answer
C. Magnesium (Mg)Explanation
The element with 12 protons, 12 neutrons, and 12 electrons is magnesium (Mg). The atomic number of an element is equal to the number of protons in its nucleus. Since magnesium has 12 protons, it has an atomic number of 12. The atomic mass of an element is the sum of the number of protons and neutrons in its nucleus. Since magnesium has 12 protons and 12 neutrons, its atomic mass is 24. The number of electrons in an atom is equal to the number of protons, so magnesium also has 12 electrons.Rate this question:
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- 14.
What is the name of an atom with an atomic mass number of 18 and 8 protons?
- A.
Oxygen-8
- B.
Oxygen-16
- C.
Oxygen-18
- D.
Oxygen-26
Correct Answer
C. Oxygen-18Explanation
The correct answer is Oxygen-18. The atomic mass number of an atom is determined by the sum of its protons and neutrons. In this case, the atom has 8 protons, so it is oxygen. The atomic mass number is 18, indicating that there are 10 neutrons present in the nucleus.Rate this question:
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- 15.
True or False: Calcium (Ca) always has 20 protons.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Calcium (Ca) is an element with an atomic number of 20, which indicates the number of protons in its nucleus. Therefore, it always has 20 protons.Rate this question:
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- 16.
True or False: Na+ is an anion.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement "Na+ is an anion" is false. Na+ refers to a sodium ion, which is a cation. Anions are negatively charged ions, while cations are positively charged ions. In the case of Na+, the sodium atom has lost an electron, resulting in a positive charge.Rate this question:
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- 17.
What is the name for the ion CO32- ?
- A.
Carbon Trioxide
- B.
Carbonoxide
- C.
Carbonate
Correct Answer
C. CarbonateExplanation
The correct answer is "Carbonate". Carbonate is the name for the ion CO32-. It is formed when carbon dioxide reacts with water and forms a weak acid called carbonic acid. The carbonate ion is commonly found in minerals such as limestone and is an important component in the carbon cycle.Rate this question:
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- 18.
What is the formula for Aluminum (III) Sulfate?
- A.
Al3SO4
- B.
Al3S
- C.
Al2(SO4)3
- D.
Al2S3
Correct Answer
C. Al2(SO4)3Explanation
The correct formula for Aluminum (III) Sulfate is Al2(SO4)3. This is because Aluminum has a +3 charge, while Sulfate (SO4) has a -2 charge. In order to balance the charges, two Aluminum ions are needed to combine with three Sulfate ions, resulting in the formula Al2(SO4)3.Rate this question:
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- 19.
What is the name for Cu(NO3)2?
- A.
Copper Nitride
- B.
Copper Trinitrate
- C.
Copper (I) Nitrate
- D.
Copper (II) Nitrate
Correct Answer
D. Copper (II) NitrateExplanation
The correct answer is Copper (II) Nitrate. This is because the compound Cu(NO3)2 consists of copper (Cu) ions with a charge of +2 and nitrate (NO3) ions, which have a charge of -1. To balance the charges, two nitrate ions are needed for every copper ion, resulting in the formula Cu(NO3)2. Therefore, the correct name for this compound is Copper (II) Nitrate.Rate this question:
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- 20.
Is OH- an element, ion, or compound?
- A.
Element
- B.
Ion
- C.
Compound
Correct Answer
B. IonExplanation
OH- is an ion. An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a positive or negative charge. OH- is a negatively charged ion, also known as a hydroxide ion. It is formed when a hydrogen atom in a water molecule loses its electron.Rate this question:
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- 21.
What term describes the process of a substance changing from solid to gas?
- A.
Condensation
- B.
Deposition
- C.
Sublimation
- D.
Evaporation
Correct Answer
C. SublimationExplanation
Sublimation is the correct answer because it refers to the process in which a substance transitions directly from a solid state to a gas state without passing through the liquid phase. This occurs when the substance is heated and its particles gain enough energy to break free from the solid structure and enter the gas phase. Examples of substances that undergo sublimation include dry ice (solid carbon dioxide) and mothballs (naphthalene).Rate this question:
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- 22.
Which of the following is a chemical change?
- A.
Glass breaking
- B.
Inflating a basketball
- C.
A towel absorbing water
- D.
A nail rusting in the rain
Correct Answer
D. A nail rusting in the rainExplanation
A nail rusting in the rain is a chemical change because it involves a reaction between the iron in the nail and the oxygen in the air, resulting in the formation of iron oxide (rust). This reaction changes the chemical composition of the nail, making it a chemical change. The other options, such as glass breaking, inflating a basketball, and a towel absorbing water, are all physical changes that do not involve a change in the chemical composition of the substances involved.Rate this question:
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- 23.
True or False: An example of qualitative data is color.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
An example of qualitative data is color because qualitative data is descriptive and subjective in nature, and color is a characteristic that can be described and is subjective to individual perception. It does not involve numerical measurements or quantities, but rather focuses on qualities and characteristics. Therefore, color can be considered as qualitative data.Rate this question:
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- 24.
Which of the following characteristics of a person are quantitative? (You may select multiple answers)
- A.
Hair color
- B.
Height
- C.
Skin tone
- D.
Weight
- E.
Age
Correct Answer(s)
B. Height
D. Weight
E. AgeExplanation
The characteristics of height, weight, and age are considered quantitative because they can be measured and expressed numerically. These attributes can be quantified using specific units of measurement, such as inches or centimeters for height, pounds or kilograms for weight, and years for age. On the other hand, hair color and skin tone are qualitative characteristics that cannot be easily measured or expressed numerically.Rate this question:
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- 25.
Which of the following describes a heterogeneous substance containing large solid particles?
- A.
Compound
- B.
Colloid
- C.
Suspension
- D.
Solution
Correct Answer
C. SuspensionExplanation
A suspension is a heterogeneous substance that contains large solid particles that are dispersed in a liquid or gas. Unlike solutions, where the particles are evenly distributed and do not settle, suspensions have particles that are visible and can settle over time. This can be seen in examples like muddy water or sand in water. Suspensions can be separated through methods such as filtration or settling.Rate this question:
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- 26.
What is the percent composition of Oxygen in Al(OH)3?
- A.
61.5%
- B.
20.5%
- C.
36.4%
- D.
65.4%
Correct Answer
A. 61.5%Explanation
The percent composition of Oxygen in Al(OH)3 is 61.5%. This can be calculated by finding the molar mass of Oxygen in Al(OH)3 and dividing it by the molar mass of Al(OH)3, then multiplying by 100. In Al(OH)3, there are 3 Oxygen atoms with a molar mass of 16 g/mol each, so the total mass of Oxygen is 48 g/mol. The molar mass of Al(OH)3 is 78 g/mol. Dividing 48 g/mol by 78 g/mol and multiplying by 100 gives us 61.5%.Rate this question:
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- 27.
What is the percent composition of Oxygen in Cu2(SO4)3?
- A.
18.2%
- B.
54.7%
- C.
28.7%
- D.
46.3%
Correct Answer
D. 46.3%Explanation
In Cu2(SO4)3, there are a total of 3 oxygen atoms. To calculate the percent composition of oxygen, we need to find the molar mass of oxygen and the molar mass of the entire compound. The molar mass of oxygen is 16 g/mol, and the molar mass of Cu2(SO4)3 is 2(63.5) + 3(32 + 4(16)) = 2(63.5) + 3(32 + 64) = 2(63.5) + 3(96) = 127 + 288 = 415 g/mol. Therefore, the percent composition of oxygen is (3 * 16 g/mol / 415 g/mol) * 100% = 46.3%.Rate this question:
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- 28.
What is the percent composition of Sodium in NaCl?
- A.
50.0%
- B.
39.3%
- C.
60.7%
- D.
58.5%
Correct Answer
B. 39.3%Explanation
The percent composition of an element in a compound is the mass percentage of that element in the compound. In the case of NaCl, the compound consists of one sodium atom (Na) and one chlorine atom (Cl). The molar mass of Na is 22.99 g/mol and the molar mass of Cl is 35.45 g/mol. To calculate the percent composition of sodium in NaCl, we divide the molar mass of sodium by the molar mass of NaCl and multiply by 100. (22.99 g/mol / 58.44 g/mol) * 100 = 39.3%. Therefore, the correct answer is 39.3%.Rate this question:
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- 29.
What is the mass number of the element Tin (Sn)?
- A.
118.7
- B.
50
- C.
168.7
- D.
78.7
Correct Answer
A. 118.7 -
- 30.
What is the molar mass of Potassium Chloride?
- A.
36.0
- B.
39.1
- C.
35.5
- D.
74.6
Correct Answer
D. 74.6Explanation
Potassium chloride (KCl) is composed of one potassium atom (atomic mass 39.1 g/mol) and one chlorine atom (atomic mass 35.5 g/mol). To calculate the molar mass of KCl, we add the atomic masses of the two atoms together: 39.1 + 35.5 = 74.6 g/mol. Therefore, the molar mass of potassium chloride is 74.6 g/mol.Rate this question:
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- 31.
What is the molar mass of Copper (II) Carbonate?
- A.
139.0
- B.
91.5
- C.
107.5
- D.
123.5
Correct Answer
D. 123.5Explanation
The molar mass of Copper (II) Carbonate is 123.5. This can be determined by adding up the atomic masses of all the elements present in the compound. Copper has a molar mass of 63.5, carbon has a molar mass of 12.0, and oxygen has a molar mass of 16.0. Since there are two oxygen atoms in the compound, their molar mass is multiplied by 2. Adding up these values gives a total molar mass of 123.5.Rate this question:
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- 32.
What is the molar mass of Sodium Hydroxide?
- A.
24.0
- B.
40.0
- C.
42.0
- D.
56.0
Correct Answer
B. 40.0Explanation
The molar mass of Sodium Hydroxide (NaOH) is 40.0 g/mol. This is calculated by adding the atomic masses of each element in the compound: Sodium (Na) has an atomic mass of 23.0 g/mol, Oxygen (O) has an atomic mass of 16.0 g/mol, and Hydrogen (H) has an atomic mass of 1.0 g/mol. Adding these together gives a molar mass of 40.0 g/mol.Rate this question:
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- 33.
How many protons are present in an atom of Silver (Ag)?
- A.
108
- B.
94
- C.
61
- D.
47
Correct Answer
D. 47Explanation
The correct answer is 47 because the atomic number of an element represents the number of protons in its nucleus. Since the question is asking about an atom of silver (Ag), which is a specific element, we can refer to the periodic table to find the atomic number of silver, which is 47. Therefore, an atom of silver contains 47 protons.Rate this question:
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- 34.
What describes a substance that is firm where molecules can only vibrate in place?
- A.
Solid
- B.
Liquid
- C.
Gas
Correct Answer
A. SolidExplanation
A substance that is firm and where molecules can only vibrate in place is called a solid. In a solid, the molecules are tightly packed together and have strong intermolecular forces that prevent them from moving freely. This results in a rigid structure where the molecules can only vibrate around their fixed positions. Solids have a definite shape and volume, unlike liquids and gases which can flow and take the shape of their container.Rate this question:
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- 35.
What describes a substance that can change shape but has a fixed volume and its molecules are loose?
- A.
Solid
- B.
Liquid
- C.
Gas
Correct Answer
B. LiquidExplanation
A substance that can change shape but has a fixed volume and its molecules are loose is called a liquid. Liquids have a definite volume but take the shape of their container. The molecules in a liquid are not tightly packed like in a solid, allowing them to move and flow more freely. This characteristic gives liquids their ability to change shape while maintaining a fixed volume.Rate this question:
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- 36.
What describes a substance that has no definite shape or volume and its molecules are completely free?
- A.
Solid
- B.
Liquid
- C.
Gas
Correct Answer
C. GasExplanation
A gas is a substance that has no definite shape or volume and its molecules are completely free. Unlike solids and liquids, which have a fixed shape and volume, the molecules in a gas are not bound together and are able to move freely. This allows gases to fill the space available to them and expand to fill any container. Examples of gases include oxygen, nitrogen, and carbon dioxide.Rate this question:
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- 37.
Which term describes the process of gathering information?
- A.
Creating a Hypothesis
- B.
Doing an Experiment
- C.
Drawing a Conclusion
- D.
Researching
Correct Answer
D. ResearchingExplanation
Researching is the term that describes the process of gathering information. This involves conducting a systematic investigation, collecting and analyzing data, and obtaining relevant information from various sources such as books, articles, interviews, surveys, or experiments. Researching is an essential step in acquiring knowledge, understanding a topic, and making informed decisions or drawing conclusions based on the collected information.Rate this question:
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- 38.
Which term describes the process of testing a hypothesis?
- A.
Creating a Hypothesis
- B.
Doing an Experiment
- C.
Drawing a Conclusion
- D.
Researching
Correct Answer
B. Doing an ExperimentExplanation
The term that describes the process of testing a hypothesis is "Doing an Experiment." This involves designing and conducting a controlled investigation to gather data and evidence that either supports or refutes the hypothesis. By conducting an experiment, scientists can manipulate variables and observe the resulting outcomes, which helps to validate or invalidate the proposed hypothesis.Rate this question:
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- 39.
True or False: An neutron is negatively charged.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement is false because a neutron is a subatomic particle that does not have a charge. It is electrically neutral, meaning it does not have a positive or negative charge.Rate this question:
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- 40.
Which part(s) of an atom are located in the nucleus?
- A.
Proton
- B.
Neutron
- C.
Electron
Correct Answer(s)
A. Proton
B. NeutronExplanation
Protons and neutrons are located in the nucleus of an atom. The nucleus is the central part of an atom that contains most of its mass. Protons have a positive charge, while neutrons have no charge. Electrons, on the other hand, are located outside the nucleus in electron shells and have a negative charge. Therefore, the correct answer is Proton, Neutron.Rate this question:
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- 41.
What is the complete electron configuration for Chlorine (Cl)?
- A.
1p22p22s63p23s5
- B.
1s22s22p63s23p5
- C.
3p5
- D.
1s22s22p63s23p6
Correct Answer
B. 1s22s22p63s23p5Explanation
The electron configuration for an atom represents the arrangement of its electrons in different energy levels and orbitals. In the case of Chlorine (Cl), the electron configuration is 1s22s22p63s23p5. This means that Chlorine has 17 electrons in total. The first energy level (1s) contains 2 electrons, the second energy level (2s) contains 2 electrons, the second energy level (2p) contains 6 electrons, the third energy level (3s) contains 2 electrons, and the third energy level (3p) contains 5 electrons.Rate this question:
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- 42.
Which element is represented by: 1s22s22p63s23p64s23d104p65s24d2?
- A.
Titanium (Ti)
- B.
Zirconium (Zr)
- C.
Hafnium (Hf)
- D.
Rutherfordium (Rf)
Correct Answer
B. Zirconium (Zr)Explanation
The electron configuration provided corresponds to Zirconium (Zr). The electron configuration represents the distribution of electrons in the different energy levels and orbitals of an atom. In this case, the numbers and letters indicate the number of electrons in each orbital. The electron configuration given matches the electron configuration of Zirconium, which has 2 electrons in the 1s orbital, 2 electrons in the 2s orbital, 6 electrons in the 2p orbital, 2 electrons in the 3s orbital, 6 electrons in the 3p orbital, 2 electrons in the 4s orbital, and 2 electrons in the 3d orbital.Rate this question:
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- 43.
Which element is represented by: [Ar]4s23d104p3?
- A.
Arsenic (As)
- B.
Argon (Ar)
- C.
Antimony (Sb)
- D.
Krypton (Kr)
Correct Answer
A. Arsenic (As)Explanation
The electron configuration [Ar]4s23d104p3 represents the element Arsenic (As). The [Ar] indicates that the electron configuration starts with the noble gas Argon (Ar), which has the configuration 1s22s22p63s23p6. The following 4s23d104p3 configuration belongs to Arsenic, which has an atomic number of 33. Therefore, the correct answer is Arsenic (As).Rate this question:
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- 44.
Where are valence electrons located?
- A.
The innermost electron shell
- B.
The second electron shell
- C.
The outermost electron shell
Correct Answer
C. The outermost electron shellExplanation
Valence electrons are located in the outermost electron shell. These are the electrons involved in chemical bonding and determining the reactivity of an atom. The outermost shell, also known as the valence shell, is responsible for forming bonds with other atoms to achieve a stable electron configuration.Rate this question:
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- 45.
How many electrons are needed to fill the innermost electron shell?
- A.
2
- B.
4
- C.
6
- D.
8
Correct Answer
A. 2Explanation
The innermost electron shell, also known as the first shell, can hold a maximum of 2 electrons. This is because the first shell consists of only one subshell, which is the s subshell, and this subshell can hold a maximum of 2 electrons. Therefore, 2 electrons are needed to fill the innermost electron shell.Rate this question:
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- 46.
How many electrons are needed to fill the electron shells beyond the first one?
- A.
2
- B.
4
- C.
6
- D.
8
Correct Answer
D. 8Explanation
The electron shells beyond the first one can hold a maximum of 8 electrons. This is based on the octet rule, which states that atoms tend to gain, lose, or share electrons in order to have a full outer shell of 8 electrons. Therefore, 8 electrons are needed to fill the electron shells beyond the first one.Rate this question:
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- 47.
Cl is changed to Cl-. What must have happened?
- A.
Cl lost an electron
- B.
Cl gained an electron
- C.
Cl lost a proton
- D.
Cl gained a proton
Correct Answer
B. Cl gained an electronExplanation
When Cl is changed to Cl-, it means that Cl has gained an electron. This is because Cl- indicates that chlorine now has one more electron than its neutral state, Cl. Electrons have a negative charge, so when an atom gains an electron, it becomes negatively charged. Therefore, Cl gaining an electron is the most plausible explanation for the given scenario.Rate this question:
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- 48.
According to Bohr's model of the atom:
- A.
Electrons orbit the nucleus in random paths.
- B.
Electrons move in fixed orbits at specific energy levels.
- C.
Electrons and protons are evenly distributed in the nucleus.
- D.
Electrons are continuously moving towards the nucleus.
Correct Answer
B. Electrons move in fixed orbits at specific energy levels.Explanation
Bohr's model revolutionized atomic theory by proposing that electrons orbit the nucleus in fixed paths at specific energy levels. This quantized arrangement explains the stability of atoms, as electrons neither spiral into the nucleus nor escape into infinity. The model laid the foundation for understanding the discrete nature of electron orbits.Rate this question:
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- 49.
In Bohr's model, when an electron moves from a higher energy level to a lower one:
- A.
It absorbs energy.
- B.
It emits energy.
- C.
It remains in the same energy level.
- D.
Its energy level becomes unpredictable.
Correct Answer
B. It emits energy.Explanation
In Bohr's atomic model, when an electron moves from a higher energy level to a lower one, it releases energy as a photon. This emission occurs as the electron's energy decreases and stabilizes in a lower orbit. The concept elucidates the quantized nature of energy levels and photon emission in atomic systems.Rate this question:
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- 50.
How many valence electrons does a Strontium (Sr) atom have?
- A.
8
- B.
2
- C.
4
- D.
6
Correct Answer
B. 2Explanation
The outermost electron shell, known as the valence shell, houses electrons crucial to an atom's chemical behavior, called valence electrons. Examining Strontium (Sr) with 38 electrons reveals its electron distribution: K-shell (2 electrons), L-shell (8 electrons), M-shell (18 electrons), N-shell (8 electrons), and the valence shell (2 electrons). Consequently, Strontium possesses 2 valence electrons, influencing its interaction in chemical reactions.Rate this question:
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Dec 21, 2023Quiz Edited by
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Dec 11, 2011Quiz Created by
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