# 4.1: Homework Chapter 4


GENERAL QUESTIONS

1. List the three statements that make up the modern atomic theory.

2.      Define atomic number. What is the atomic number for a boron atom?

3.      Which elements are alkali metals, alkaline earth metals, and halogens?

a.       sodium

b.      magnesium

c.       calcium

d.      chlorine

e.       potassium

f.        bromine

4.      Two of the most well-known isotopes of carbon are carbon-12 and carbon-14. Answer the following:

a.       What is the atomic number of each isotope?

b.      What is the mass number of each isotope?

ATOMIC AND NUCLEAR THEORY

5.      What happened to most of the alpha particles in Rutherford’s experiment?

1. What is the modern atomic theory?

7.      Describe why Rutherford used the term planetary model to describe his model of atomic structure?

PROTONS, NEUTRONS, AND ELECTRONS

8.      What are the charges for each of the three subatomic particles?

9.       Of the three subatomic particles, which is the least massive? Which of the subatomic particles are located inside the nucleus of the atom?

10.  Circle one item in each parenthesis.  Protons are among the (most, least) massive subatomic particles, and they are found (inside, outside) the nucleus.

11.  Which subatomic particle has a positive charge? Which subatomic particle has a negative charge?

12.  Which subatomic particle is electrically neutral? Does it exist inside or outside the nucleus?

13.  Circle one item in each parenthesis.  Electrons are among the (most, least) massive subatomic particles, and they are found (inside, outside) the nucleus.

ELEMENTS, SYMBOLS, AND NAMES

14.   Of the three subatomic particles that make up an element, which one can always be used to identify the element?

15.   Identify the atomic symbols and names of the elements that correspond to the following atomic numbers:

a.       8

b.      27

c.       33

d.      90

16.  How many protons are in the nucleus of an atom of each element?

a.       fluorine

b.      magnesium

c.       iodine

d.      copper

e.       silicon

17.  Which elements contain the following numbers of protons?

a.       15

b.      42

c.       4

18.  Which of the following substances are elements?

a.       sodium

b.      carbon

c.       gold

d.      water

f.        liquefied nitrogen

19.  Write the chemical symbol for each element.

a.       silver

b.      sulfur

c.       nitrogen

d.      neon

20.   List the name and the atomic number of each element.

a.       F

b.      Fe

c.       I

d.      Cr

e.       P

21.  How many protons are in the nucleus of each element?

b.      tungsten

c.       chromium

d.      beryllium

22.  Find the atomic number for each element.

a.       Ni

b.      Sr

c.       Se

d.      Cs

THE PERIODIC TABLE

23.   One of the main groups on the periodic tables is the Metals. How many different subgroups of metals are there on the periodic table? Name each of them. Where in the periodic table can each subgroup be located? Be specific (provide the column number).

24.  Apart from Metals, there are Metalloids and Non-Metals as groups on the periodic table. Name at least two subgroups within the Non-Metals. Where on the periodic table are these subgroups located? Be specific (provide the column number).

25.  How do the transition metals differ from the alkali and alkaline earth metals?

26.   Of the following elements, which of the three categories, metal, non-metal and metalloid, do they each belong to?

a.       manganese

b.      bromine

c.       silicon

d.      uranium

e.       phosphorus

27.  Which elements have chemical properties similar to those of magnesium?

a.       sodium

b.      fluorine

c.       calcium

d.      barium

e.       selenium

28.  Which elements are alkali metals?

a.       sodium

b.      magnesium

c.       potassium

d.      aluminum

e.       beryllium

29.  Which elements are alkaline earth metals?

a.       sodium

b.      magnesium

c.       potassium

d.      aluminum

e.       beryllium

30.  Which elements are halogens?

a.       oxygen

b.      chlorine

c.       fluorine

d.      sulfur

e.       argon

31.  Which elements are noble gases?

a.       helium

b.      hydrogen

c.       oxygen

d.      xenon

e.       neon

32.  Which pairs of elements are located in the same period?

a.       H and Li

b.      H and He

c.       Na and S

d.      Na and Rb

33.   Circle one item in each parenthesis.  Scandium is a (metal, nonmetal, semimetal) and is a member of the (main group elements, transition metals).

34.  Which of these sets of elements are all in the same group?

a.       sodium, rubidium, and barium

b.      nitrogen, phosphorus, and bismuth

c.       copper, silver, and gold

d.      magnesium, strontium, and samarium

35.  Which elements are alkali metals?

a.       Rubidium

b.      Tin

c.       Gold

d.      Sodium

36.  Provide the family or group name of each element.

a.       Li

b.      Ar

c.       Cl

37.  To what group number does each element belong?

a.       sodium

b.      cesium

c.       argon

d.      tellurium

38.  Which elements do you expect to be most like Strontium?

a.       beryllium

d.      potassium

39.  Complete the table below

 Chemical Symbol Group Number Group Name Metal or Non-metal Br Sr 2A Ne Non-metal K Alkali metal

40.  Which pair of elements do you expect to be most similar?

a.       V and W

b.      Mg and Ca

c.       Cr and Tc

d.      Ga and Si

41.  Which elements are alkaline earth metals?

b.      scandium

c.       cesium

d.      beryllium

42.  Which element is a main-group non-metal?

a.       S

b.      K

c.       Fe

d.      Ca

43.  Which elements would you expect to lose electrons in chemical changes?

a.       copper

b.      barium

c.       fluorine

d.      sulfur

IONS

44.   What is the total number of electrons present in each ion?

a.       F

b.      Rb+

c.       Ce3+

d.      Zr4+

e.       Zn2+

45.   Predict how many electrons are in each ion.

a.       A copper ion with a +2 charge

b.      a molybdenum ion with a +4 charge

c.       an iodine ion with a −1 charge

d.      a gallium ion with a +3 charge

46.  What is the total number of electrons present in each ion?

a.       Ca2+

b.      Se2−

c.       In3+

d.      Sr2+

e.       As3+

47.  Predict how many electrons are in each ion.

a.       an oxygen ion with a −2 charge

b.      a beryllium ion with a +2 charge

c.       a silver ion with a +1 charge

d.      a selenium ion with a +4 charge

48.  Predict the charge on the most common monatomic ion formed by each element.

a.       chlorine

b.      phosphorus

c.       scandium

d.      magnesium

49.   For each representation of a monatomic ion, identify the parent atom, write the formula of the ion using an appropriate superscript, and indicate the period and group on the periodic table in which the element is found.

a.    +

b.    -

c.    3+

50.  Predict the charge on the most common monatomic ion formed by each element.

a.       sodium

b.      selenium

c.       barium

d.      aluminum

51.  Predict how many electrons each element will most likely gain or lose.

a.       Ca

b.      N

c.       P

d.      Rb

52.  Predict the ion formed by each element?

a.       Li

b.      Cl

c.       K

d.      O

53.  Give the charge each atom takes when it forms an ion. If more than one charge is possible, list both.

a.       K

b.      O

c.       Co

54.  Give the charge each atom takes when it forms an ion. If more than one charge is possible, list both.

a.       Ag

b.      Au

c.       Br

1. What is the difference between SO3 and SO32−?

ISOTOPES

56.  What is an isotope? How does one isotope differ from another within the same element?

57.    What do all isotopes of nitrogen have in common? Is this true for isotopes of all elements?

58.  Starting with polonium, atomic number 84, there are no stable, non-radioactive isotopes of any subsequent elements on the periodic table. Using the atomic symbol and the mass and atomic numbers, express the isotope of polonium-84.

59.   Determine the atomic number and mass number for each isotope.

a.       the hydrogen isotope with 2 neutrons

b.      the calcium isotope with 22 neutrons

c.       the tantalum isotope with 109 neutrons

d.      the chromium isotope with 28 neutrons

60.  State the number of protons, neutrons, and electrons in neutral atoms of each isotope.

a.       131I

b.      40K

c.       201Hg

d.      19F

61.  Complete each sentence.

a.       48Ti has _____ neutrons.

b.      40Ar has _____ neutrons.

c.       3H has _____ neutrons.

62.  What is the mass number of a gallium atom that has 38 neutrons in it?

63.  Give the symbol   for these isotopes.

a.       Fluorine-19

b.      Helium-4

c.       Terbium-159

d.      Iodine-127

e.       Gold-197

64.   Identify each element, represented by X, that has the given symbols and determine the number of protons and neutrons in each isotope.

a.

b.

c.

d.

65.  Determine the number of protons, neutrons, and electrons in a neutral atom of each isotope:

a.       97Tc

b.      113In

c.       63Ni

d.      55Fe

66.   Both technetium-97 and americium-240 are produced in nuclear reactors. Determine the number of protons, neutrons, and electrons in the neutral atoms of each.

67.   The following isotopes are important in archaeological research. How many protons, neutrons, and electrons does a neutral atom of each contain?

a.       207Pb

b.      16O

c.       137Cs

d.      40K

68.  Give complete symbols of each atom, including the atomic number and the mass number.

a.       a magnesium atom with 12 protons and 12 neutrons

b.      a magnesium atom with 12 protons and 13 neutrons

c.       a xenon atom with 54 protons and 77 neutrons

69.  How many protons and neutrons are in   ?

70.  Plutonium-239 is used in nuclear bombs. Determine the number of protons and neutrons in Plutonium-239 and write its symbol in the form  .

CUMULATIVE PROBLEMS

71.  Using the given clues, determine the identity of the following elements:

a.       A noble gas with an atomic number less than 10

b.      A metalloid from period 2

c.       A group 5A element directly adjacent to a metalloid

72.  Complete the following table.

 Isotope Symbol Number of protons Number of neutrons Number of electrons Mass Number C-12 C-13 C-14

73.  Complete the following table.

 Number of protons Number of neutrons Element name Isotope Symbol 80 120 2 Hydrogen

74.  Classify each element as a metal, a semimetal, or a nonmetal. If a metal, state whether it is an alkali metal, an alkaline earth metal, or a transition metal.

a.       iron

b.      tantalum

c.       sulfur

d.      silicon

e.       chlorine

75.  Explain why it is improper to write CO as the chemical symbol for cobalt?

76.  Write the appropriate symbol for each of the following ions (Example:  59Co3+):

a.       the ion with a 1+ charge, atomic number 55, and mass number 133

b.      the ion with 54 electrons, 53 protons, and 74 neutrons

c.        the ion with atomic number 15, mass number 31, and a 3− charge

d.       the ion with 24 electrons, 30 neutrons, and a 3+ charge

77.  The following are properties of isotopes of two elements that are essential in our diet. Determine the number of protons, neutrons and electrons in each and name each element.

a.        atomic number 26, mass number 58, charge of 2+

b.      atomic number 53, mass number 127, charge of 1−

78.   Fill in the blanks to complete the table.

 Symbol Ion commonly formed Number of electrons in ion Number of protons in ion F 9 Be2+ 2 Br 36 Al 13 O

79.  An isotope of uranium has an atomic number of 92 and a mass number of 235. What are the number of protons and neutrons in the nucleus of this atom?

80.  Under certain conditions, oxygen gas (O2) has a density of 0.00134 g/mL.  Find the volume occupied by 250.0 g of O2 under the same conditions.

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