CHAPTER 4: ATOMS 11/21/19 NAME: ROW PD

[Pages:4]NAME: _____________________

CHAPTER 4: ATOMS

11/21/19 ROW ______ PD ______

1 The three nuclides, U-233, U-235, and U-238, are isotopes of uranium because they have the same number of protons per atom and

1) a different number of electrons per atom 3) the same number of electrons per atom

2) the same number of neutrons per atom 4) a different number of neutrons per atom

2 Which quantity can vary among atoms of the same element?

1) atomic number 3) mass number

2) number of protons 4) numbers of electrons

3 A sample composed only of atoms having the same atomic number is classified as

1) a solution 3) a element

2) an isomer 4) a compound

4 Which statement describes the distribution of charge in an atom?

1) A positively charged nucleus is surrounded by one or more positively charged electrons.

2) A neutral nucleus is surrounded by one or more positively charged electrons.

3) A neutral nucleus is surrounded by one or more negatively charged electrons.

4) A positively charged nucleus is surrounded by one or more negatively charged electrons.

5 Which symbol represents a particle that has a mass approximately equal to the mass of a neutron?

1) p

2) ?

3)

4) +

6 On the Periodic Table, the number of protons in an atom of an element is indicated by its

1) number of valence electrons 2) selected oxidation states 3) atomic mass 4) atomic number

7 Which change occurs when an atom in an excited state returns to the ground state?

1) Energy is emitted. 2) The number of electrons increases. 3) The number of electrons decreases. 4) Energy is absorbed.

8 Element X has two isotopes. If 72.0% of the element has an isotopic mass of 84.9 atomic mass units, and 28.0% of the element has an isotopic mass of 87.0 atomic mass units, the average atomic mass of element X is numerically equal to

1) 2) 3) 4)

9 Which electron shell in an atom of calcium in the ground state has an electron with the greatest amount of energy?

1) 3

2) 4

3) 2

4) 1

10 The weighted average of the atomic masses of the naturally occurring isotopes of an element is the

1) atomic number of the element 2) mass number of each isotope 3) atomic mass of the element 4) formula mass of each isotope

11 Compared to an atom of C-12, an atom of C-14 has a greater

1) mass number 3) atomic number

2) number of electrons 4) number of protons

12 An orbital is a region in an atom where there is a high probability of finding

13 The gold foil experiment led to the conclusion that each atom in the foil was composed mostly of empty space because most alpha particles directed at the foil

1) passed through the foil 2) were deflected by the electrons in gold atoms 3) remained trapped in the foil 4) were deflected by the nuclei in gold atoms

14 According to the wave-mechanical model of the atom, electrons are located in

1) a hard, indivisible sphere 2) a small, dense nucleus 3) orbitals 4) circular paths

15 What is the total number of neutrons in an atom of O-18?

1) 18

2) 16

3) 10

4) 8

16 An orbital is a region of space where there is a high probability of finding

1) a positron 3) an electron

2) a neutron 4) a proton

17 How do the energy and the most probable location of an electron in the third shell of an atom compare to the energy and the most probable location of an electron in the first shell of the same atom?

1) In the third shell, an electron has more energy and is farther from the nucleus.

2) In the third shell, an electron has more energy and is closer to the nucleus.

3) In the third shell, an electron has less energy and is farther from the nucleus.

4) In the third shell, an electron has less energy and is closer to the nucleus.

18 Each diagram below represents the nucleus of a different atom.

Which diagrams represent nuclei of the same element?

1) Q, R, and E 3) D and E, only

2) Q and R, only 4) D, E, and Q

19 Compared to the energy of an electron in the second shell of an atom of sulfur, the energy of an electron in the

1) first shell is lower 3) first shell is the same

2) third shell is lower 4) third shell is the same

20 Which statement about the mass of an electron is correct?

1) The mass of an electron is greater than the mass of a neutron.

2) The mass of an electron is less than the mass of a proton. 3) The mass of an electron is equal to the mass of a proton. 4) The mass of an electron is equal to the mass of a neutron.

21 Which electron configuration represents the electrons in an atom of sodium in the ground state at STP?

1) 2-8-1 2) 2-8-6 3) 2-7-2 4) 2-7-7

1) a neutron 3) an alpha particle

2) an electron 4) a positron

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CHAPTER 4: ATOMS

22 The table below gives the atomic mass and the abundance of the two naturally occurring isotopes of chlorine.

Which numerical setup can be used to calculate the atomic mass of the element chlorine?

1) (34.97 u)(0.2424) + (36.97 u)(0.7576) 3) (34.97 u)(75.76) + (36.97 u)(24.24)

2) (34.97 u)(0.7576) + (36.97 u)(0.2424) 4) (34.97 u)(24.24) + (36.97 u)(75.76)

23 Which electron configuration represents an atom of chlorine in an excited state?

1) 2-7-8

2) 2-8-7-2

3) 2-8-7

4) 2-8-8

Base your answers to questions 24 and 25 on your knowledge of chemistry and the bright-line spectra produced by four elements and the spectrum of a mixture of elements represented in the diagram below.

24 Each line in the spectra represents the energy

1) released as an electron moves from a lower energy state to a higher energy state 2) absorbed as an atom loses an electron 3) released as an electron moves from a higher energy state to a lower energy state 4) absorbed as an atom gains an electron

25 Which elements are present in this mixture?

1) D and Z

2) X and Z

3) D and A

4) X and A

Base your answers to questions 26 and 27 on the information below and on your knowledge of chemistry.

The only natural occurring isotopes of nitrogen are N-14 and N-15. 26 State the number of electrons in each shell of a N-14 atom in the ground state.

27 State the number of protons in an atom of N-15.

28 Base your answer to the following question on the information below and on your knowledge of chemistry.

Fireworks that contain metallic salts such as sodium, strontium, and barium can generate bright colors. A technician investigates what colors are produced by the metallic salts by performing flame tests. During a flame test, a metallic salt is heated in the flame of a gas burner. Each metallic salt emits a characteristic colored light in the flame. Explain why the electron configuration of 2-7-1-1 represents a sodium atom in an excited state.

29 Base your answer to the following question on the information below.

Elements with atomic numbers 112 and 114 have been produced and their IUPAC names are pending approval. However, an element that would be put between these two elements on the Periodic Table has not yet been produced. If produced, this element will be identified by the symbol Uut until an IUPAC name is approved. Determine the charge of an Uut nucleus. Your response must include both the numerical value and the sign of the charge.

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CHAPTER 4: ATOMS

Base your answers to questions 30 through 32 on the information below and on your knowledge of chemistry. A student compares some models of the atom. These models are listed in the table below in order of development

from top to bottom.

30 Using the conclusion from the Rutherford model, identify the charged subatomic particle that is located in the nucleus. 31 State one conclusion about the internal structure of the atom that resulted from the gold foil experiment. 32 State the model that first included electrons as subatomic particles. 33 Base your answer to the following question on the information below and on your knowledge of chemistry.

Some isotopes of neon are Ne-19, Ne-20, Ne-21, Ne-22, and Ne-24. The neon-24 decays by beta emission. The atomic mass and natural abundance for the naturally occurring isotopes of neon are shown in the table below.

Show a numerical setup for calculating the atomic mass of neon.

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Answer Key CHAPTER 4: ATOMS

1

4

2

3

3

3

4

4

5

1

6

4

7

1

8

2

9

2

10

3

11

1

12

2

13

1

14

3

15

3

16

3

17

1

18

4

19

1

20

2

21

1

22

2

23

1

24

3

25

4

26 First shell: 2 Second shell: 5

32 -- Thomson model -- Thomson -- plum pudding model

33

First shell: 2e? Second shell: 5e?

27 7

28 -- The configuration represents a higher energy state than sodium's ground state, 2-8-1. -- Not all 11 electrons are in their lowest possible energy levels. -- A second shell electron has moved to the fourth shell. -- A lower shell electron is shown in a higher shell.

29 +113

30 -- proton -- p -- p+ -- 11p -- 11H -- H+

31 -- An atom is mainly empty space. -- It has a nucleus. --The small, dense nucleus is positively charged.

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