Deck 21: The Main Group Elements: Life and the Periodic Table

Question 1

Which metal, by either mass or number of atoms, is most abundant in the human body?

A)K
B)Na
C)Mg
D)Al
E)Ca

Answer 1

Ca

Question 2

Which element, by the number of atoms, is least abundant in the human body?

A)sodium
B)calcium
C)potassium
D)magnesium
E)nitrogen

Answer 2

magnesium

Question 3

What is the dominant role played by calcium in the body?

A)maintains osmotic pressure
B)transmits nerve impulses
C)forms structural materials
D)a key component in enzymes
E)important in the function of the thyroid gland

Answer 3

forms structural materials

Question 4

The concentration of an ultratrace essential element in the body is less than ________ per gram of body mass.

A)1 g
B)10 mg
C)1 mg
D)10 $\mu$ g
E)1 $\mu$ g

Question 5

Cell membranes are formed by ________

A)a lipid layer.
B)a lipid bilayer.
C)a phospholipid bilayer.
D)cellulose.
E)starch.

Question 6

The ion found in chlorophyll is ________

A)Zn²⁺
B)Mg²⁺
C)Ca²⁺
D)Fe²⁺
E)Cu²⁺

Question 7

Magnesium is found in which one of the following important biological molecules?

A)chlorophyll
B)hemoglobin
C)cytochrome C
D)ferredoxin
E)adenosine triphosphate

Question 8

Which of the following elements, by mass, is the most abundant in the universe?

A)iron
B)oxygen
C)helium
D)nitrogen
E)carbon

Question 9

The concentration of a major essential element in the body is greater than ________ per gram of body mass.

A)1 g
B)10 mg
C)1 mg
D)10 $\mu$ g
E)1 $\mu$ g

Question 10

Which element, by mass, is most abundant in the human body?

A)carbon
B)oxygen
C)hydrogen
D)nitrogen
E)calcium

Question 11

Which element, by the number of atoms, is most abundant in the human body?

A)carbon
B)oxygen
C)hydrogen
D)nitrogen
E)calcium

Question 12

Which anion is most abundant in the human body?

A)I^-
B)Br ^-
C)CO₃^2-
D)Cl^-
E)NO₃^-

Question 13

The Mg²⁺ ion plays a significant role in the human body by

A)maintaining osmotic pressure.
B)forming structure support for the body.
C)transmitting nerve impulses.
D)balancing ion flow in the bloodstream.
E)participating in ATP hydrolysis and ADP phosphorylation.

Question 14

The concentration of a trace essential element in the body is typically in the range of ________ per gram of body mass.

A)1 $\mu$ g to 1 mg
B)1 $\mu$ g to 10 mg
C)10 $\mu$ g to 10 mg
D)10 $\mu$ g to 100 mg
E)100 $\mu$ g to 100 mg

Question 15

An essential biological element ________

A)is any element detected in the organism.
B)stimulates essential biological functions.
C)is found in all organisms.
D)has beneficial physiological effects, and its absence impairs function of the organism.
E)is expensive.

Question 16

Which of the following is not a characteristic of a nonessential biological element?

A)detected in the body but has no clear biological function
B)has a stimulatory effect on biological functions
C)is incorporated into biological compounds because it is similar to essential elements
D)has clear biological functions
E)organisms require them for survival

Question 17

Which ion is important in transmitting nerve impulses?

A)Na⁺
B)Mg²⁺
C)Fe²⁺
D)Zn²⁺
E)Li⁺

Question 18

Cell membranes assemble ________

A)to orient nonpolar fatty acid chains toward the interior of the cell.
B)as a bilayer with the nonpolar portion of the bilayer on the membrane exterior.
C)to orient polar head groups toward the interior and exterior of the cell.
D)based on electrostatic attractions between phospholipid molecules.
E)with polar head groups located within the interior of the membrane.

Question 19

Which metal, by the number of atoms, is most abundant in the human body?

A)sodium
B)calcium
C)potassium
D)magnesium
E)iron

Question 20

Nickel-cadmium batteries thrown into landfills can introduce cadmium ions into the groundwater. Cadmium ions can replace ________ in bones, which can weaken them.

A)Na⁺
B)K⁺
C)Zn²⁺
D)Ca²⁺
E)Mg²⁺

Question 21

Enzymes in plants convert nitrate into ammonia. The unbalanced half-reaction equation is given below. What is the stoichiometric coefficient of water in the balanced reaction equation?

A)0
B)1
C)2
D)3
E)4

Question 22

The concentration of chloride in the human body is approximately 19 mg/g of body mass. What is this concentration in ppb (parts per billion)?

A)1.9 $\times$ 10^-2 ppb
B)1.9 $\times$ 10⁷ ppb
C)1.9 $\times$ 10⁴ ppb
D)1,900 ppb
E)190 ppb

Question 23

Ion channels in cell membranes control selective transport of ions based on what property(ies)?

A)size
B)electronegativity
C)charge
D)A and C
E)B and C

Question 24

The concentration of sodium in the human body is approximately 1.5 mg/g of body mass. What is this concentration in ppm (parts per million)?

A)1.5 $\times$ 10⁶ ppm
B)1.5 $\times$ 10^-3 ppm
C)0.015 ppm
D)1,500 ppm
E)150 ppm

Question 25

The nucleus of a cell has a pH of approximately 7.3. What is the molar concentration of hydroxide in the nucleus of a cell?

A)5.00 $\times$ 10^-8 M
B)3.27 $\times$ 10^-5 M
C)2.00 $\times$ 10^-7 M
D)3.06 $\times$ 10^-10 M
E)7.31 $\times$ 10^-4 M

Question 26

Plants convert nitrate into ammonia by using enzymes called ________

A)peptidases.
B)amylases.
C)anhydrases.
D)oxidases.
E)reductases.

Question 27

Tooth enamel is composed of the mineral hydroxyapatite. It is essentially insoluble in water with K_sp = 2.3 $\times$ 10^-59, but it reacts with weak acids in the mouth as described by one of the reaction equations below. You can determine the equilibrium constant, K, for this reaction from K_sp and K_w (the equilibrium constant for water autoionization, K_w = 1.0 $\times$ 10^-14). What is the value of K?

A)2.3 $\times$ 10 ^-73
B)4.3 $\times$ 10 ⁴⁵
C)2.3 $\times$ 10 ^-45
D)1.1 $\times$ 10 ^-14
E)9.9 $\times$ 10 ^-15

Question 28

The average concentration of calcium in the human body is 15 mg/g of body mass. What is the mass of calcium in the body of a person weighing 150 lb? (1 lb = 454 g)

A)1.0 lb
B)0.023 lb
C)23 lb
D)100 lb
E)2.3 lb

Question 29

Different concentrations of ions on either side of a cell membrane constitute a concentration cell, which is described by the Nernst equation given below. What is the electrochemical potential across a membrane when the sodium ion concentration is 0.10 M on one side of the membrane and 0.010 M on the other side, and the temperature is 37 ^$\circ$ C (body temperature)? (Given: , = -2.71 V; F =96,485 C; 1 J = 1 C V; R = 8.315 J / (mol K))
E = E ^$\circ$ - InQ

A)61.5 mV
B)26.7 mV
C)2.65 V
D)2.68 V
E)2.98 V

Question 30

How much energy must be expended by a cell to transport 1 mole of sodium ions across a membrane with an electrochemical potential of 62 mV in order to maintain this potential?

A)50 kJ
B)260 kJ
C)6.0 kJ
D)250 kJ
E)6,000 kJ

Question 31

Calcium carbonate is used to form exoskeletons. It has a solubility-product constant of 5.0 $\times$ 10 ^-9. What is the molar concentration of calcium ions in a saturated solution of calcium carbonate?

A)2.5 $\times$ 10^-9 M
B)7.1 $\times$ 10^-5 M
C)3.5 $\times$ 10 ^-5 M
D)5.0 $\times$ 10^-9 M
E)4.7 $\times$ 10 ^-7 M

Question 32

Urea is a waste product produced when the body metabolizes protein. What is the oxidation number of nitrogen in urea, (NH₂)₂CO?

A)(+3)
B)(-3)
C)1
D)(-1)
E)(-4)

Question 33

Which statement describing the mechanisms by which sodium ions pass through cell membranes is not correct?

A)Groups of proteins form ion channels for sodium ions.
B)Sodium ions can be transported by Na⁺-K⁺ pumps.
C)Membrane proteins pump sodium ions through the membrane.
D)Sodium ions form complexes with nonpolar ligands that can diffuse through the membrane.
E)Sodium ions can diffuse directly through the membrane.

Question 34

Plants convert nitrogen into ammonia. This biological nitrogen fixation is effected by enzymes called nitrogenases. The enzymes assist in the transfer of electrons. The unbalanced reaction equation is What is the stoichiometric coefficient for ammonia in the balanced reaction equation?

A)1
B)2
C)4
D)6
E)8

Question 35

Different concentrations of ions on either side of a cell membrane constitute a concentration cell, which is described by the Nernst equation given below. A cell must expend energy to maintain this concentration gradient by moving ions from one side of the membrane to the other. How much energy must be expended to transport 1 mole of sodium ions across a membrane when the sodium ion concentration is 0.10 M on one side of the membrane and 0.010 M on the other side, and the temperature is 37 ^$\circ$ C (body temperature)? (Given: , = -2.71 V; F = 96,485 C; 1 J = 1 C V; R = 8.315 J / (mol K))
E = E ^$\circ$ - InQ

A)50 kJ
B)260 kJ
C)6.0 kJ
D)250 kJ
E)6,000 kJ

Question 36

Tooth enamel is composed of the calcium compound called ________

A)hydrophilite.
B)apatite.
C)hydroxyapatite.
D)calcite.
E)andradite.

Question 37

Stomach acid is 0.16 M HCl. What is the pH of stomach acid?

A)0.80
B)8.0
C)(-0.80)
D)0.69
E)(-8.0)

Question 38

Tooth enamel is composed of the mineral hydroxyapatite. It is essentially insoluble in water with K_sp = 2.3 $\times$ 10^-59, but it reacts with weak acids in the mouth as described by one of the reaction equations below. You can determine the equilibrium constant, K, for this reaction from K_sp and K_w (the equilibrium constant for water autoionization). How do you do this?

A)K = K_wK_sp
B)K = K_w /K_sp.
C)K = K_sp /K_w
D)K = K_w = K_sp
E)K = K_w = K_sp .

Question 39

Enzymes in plants convert nitrate into ammonia. The unbalanced half-reaction equation is given below. What is the change in oxidation number of nitrogen in this reaction?

A)0
B)(+5)
C)(+3)
D)(-2)
E)(-3)

Question 40

Plants convert nitrogen into ammonia. This biological nitrogen fixation is effected by enzymes called nitrogenases. The enzymes assist in the transfer of electrons. The unbalanced reaction equation is
What is the change in the oxidation number of nitrogen in this reaction?

A)(+1)
B)(-3)
C)(+3)
D)(+2)
E)(-1)

Question 41

Plants convert nitrogen into ammonia. This biological nitrogen fixation is affected by enzymes called nitrogenases. The enzymes assist in the transfer of electrons. The unbalanced reaction equation is What is the stoichiometric coefficient for H⁺ in the balanced reaction equation?

A)1
B)2
C)4
D)6
E)8

Question 42

Selenium can substitute for sulfur in the amino acid cysteine to make the amino acid selenocysteine because ________

A)sulfur and selenium both begin with s.
B)their atomic symbols are similar.
C)both have about the same atomic radius.
D)both have the same valence electron configuration.
E)both have about the same ionization potential.

Question 43

Plants convert nitrogen into ammonia. This biological nitrogen fixation is effected by enzymes called nitrogenases. The enzymes assist in the transfer of electrons. The unbalanced reaction equation is What is the stoichiometric coefficient for the electrons in the balanced reaction equation?

A)1
B)2
C)4
D)6
E)8

Question 44

The active site of an enzyme typically contains ________

A)an alkali metal.
B)an alkaline earth metal.
C)a transition metal.
D)an actinide metal.
E)a lanthanide metal.

Question 45

Copper is a trace metal in the human body with a typical concentration of 110 mg in 75 kg of body mass. What is this concentration in units of parts per million (ppm)?

A)1.5 $\times$ 10^-6 ppm
B)1.5 ppm
C)1.1 $\times$ 10^-5 ppm
D)1.1 $\times$ 10^-7 ppm
E)150 ppm

Question 46

Vanadium is an ultratrace metal in the human body with a typical concentration of approximately 17 ng/g body mass. How many milligrams of V are there in a person weighing 185 lb? 1 lb = 454 g

A)1.43 $\times$ 10^-2 mg
B)1.43 mg
C)143 mg
D)1430 mg
E)14,300 mg

Question 47

Hydroxyapatite, which is a component of tooth enamel, is very insoluble in water. For the following reaction, K_sp = 2.3 $\times$ 10^-59. What is the molar concentration of Ca₅(PO₄)₃⁺ when the pH of the mouth is 4.0?

A)2.3 $\times$ 10^-49 M
B)2.3 $\times$ 10^-59 M
C)2.3 $\times$ 10^--55 M
D)2.3 $\times$ 10^-63 M
E)0, teeth don't dissolve!

Question 48

Selenium is an ultratrace element that is essential for life. It is used in the synthesis of ________, which is ________.

A)selenocysteine; a lipid
B)cysteine; an amino acid
C)selenocysteine; an amino acid
D)selenocysteine; a fatty acid
E)selenothymine; a nucleic acid base

Question 49

Chromium is an ultratrace metal in the human body. The typical concentration is 5.0 mg in 70.0 kg of body mass. This concentration can be expressed as ________

A)0.071 ppm or 71 pp
B)71 ppm or 0.071 ppb.
C)14 ppm or 14,000 ppb.
D)0.71 ppm or 710 ppb.
E)5.0 ppm or 500 ppb.

Question 50

Adding fluoride ions to toothpaste and drinking water to prevent tooth decay is effective because fluoride ________

A)kills decay-producing bacteria.
B)produces stronger teeth.
C)reduces the solubility of tooth enamel at low pH.
D)reduces the solubility of tooth enamel at high pH.
E)prevents halitosis.

Question 51

What is the dominant role played by iodine in the body?

A)maintains osmotic pressure
B)transmits nerve impulses
C)forms structural materials
D)a key component in enzymes
E)important in the function of the thyroid gland

Question 52

Enzymes in plants convert nitrate into ammonia. The unbalanced half-reaction equation is given below. What is the stoichiometric coefficient of the nitrite ion in the balanced reaction equation?

A)0
B)1
C)2
D)3
E)4

Question 53

Plants react urea with water to produce ammonia and carbon dioxide. This reaction is an example of a ________ reaction.

A)Redox
B)metathesis
C)hydrolysis
D)combustion
E)precipitation

Question 54

Chromium is an ultratrace metal in the human body with a typical concentration of 5.0 mg in 75 kg of body mass. What is this concentration in units of parts per billion (ppb)?

A)6.7 $\times$ 10⁷ ppb
B)6.7 $\times$ 10⁴ ppb
C)67 ppb
D)0.067 ppb
E)0.67 ppb

Question 55

Adding fluoride ions to toothpaste and drinking water converts the mineral in tooth enamel, hydroxyapatite, to fluoroapatite. This conversion is beneficial in preventing tooth decay because fluoroapatite ________

A)solubility is less pH dependent.
B)makes strong hydrogen bonds.
C)prevents halitosis.
D)repels decay-producing bacteria.
E)kills decay-producing bacteria.

Question 56

Iodine's role is very specific. It is incorporated into a hormone, ________, that regulates energy production and use.

A)melatonin
B)thyroxine
C)dopamine
D)insulin
E)iodocin

Question 57

Enzymes in plants convert nitrate into ammonia. The unbalanced half-reaction equation is given below. What is the stoichiometric coefficient of the electrons, e^-, in the balanced reaction equation?

A)1
B)2
C)3
D)4
E)5

Question 58

Fluoridation to prevent tooth decay replaces ________ with fluoride in hydroxyapatite.

A)hydroxide
B)phosphate
C)phosphide
D)calcium
E)water

Question 59

Selenocysteine is an amino acid that gets incorporated into proteins that serve as antioxidants. Evidence points to a need for a minimum daily dose of selenium of 55 $\mu$ g. How many moles of selenocysteine (C₃H₇NO₂Se, 168 g /mol) can be synthesized using this amount of selenium?

A)3.3 $\times$ 10^-7 mol
B)7.0 $\times$ 10^-7 mol
C)3.3 $\times$ 10^-4 mol
D)7.0 $\times$ 10^-4 mol
E)3.7 $\times$ 10^-7 mol

Question 60

Radioactive ⁹⁰Sr can substitute for ________ in the human body.

A)Na⁺
B)Ca²⁺
C)K⁺
D)S^2-
E)Se²⁺

Question 61

Barium is a nonessential element in the human body, but some organisms build exoskeletons using barium sulfate, which has a K_sp of 1.1 $\times$ 10^-10 at 25 ^$\circ$ C. What is the mass of barium in 1.0 L of a saturated solution of barium sulfate at 25 ^$\circ$ C?

A)4.1 $\mu$ g
B)1.4 mg
C)3.7 mg
D)7.3 $\mu$ g
E)15 ng

Question 62

Pacemakers implanted in the chests of patients with certain heart conditions are powered by a lithium/iodine PVP battery, where PVP represents polyvinylpyridine. The cell reaction and standard cell potential are given below. The standard reduction potential for Li/Li⁺ is -3.05 V. What is the standard reduction potential for the iodine PVP half-reaction? $~~~~~~~~$ 3.59 V

A)(+1.50 V)
B)(- 6.64 V)
C)(- 0.54 V)
D)(+ 6.64 V)
E)(+ 0.54 V)

Question 63

The cation BiO⁺ is found in some over-the-counter antacids. Draw the Lewis structure of this cation that satisfies the octet rule for both atoms. Based on this Lewis structure, this cation has ________ of nonbonding electrons.

A)a triple bond and two pairs
B)a single bond and six pairs
C)a double bond and three pairs
D)a single bond and four pairs
E)a quadruple bond and one pair

Question 64

Rhenium-186 has medical applications. It decays by $\beta$ emission. What isotope is formed from this decay?

A)
B)
C)
D)
E)

Question 65

Thallium-201 is used in cardiac imaging. It decays by electron capture. What isotope is produced when thallium-201 captures an electron?

A)thallium-202
B)lead-201
C)lead-202
D)mercury-201
E)mercury-202

Question 66

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What species are oxidized and reduced in the cell reaction? $~~~~~~~~$ -1.249 V $~~~~~~~~$ +0.401 V

A)Oxygen is reduced and zinc is oxidized.
B)Zinc is reduced and oxygen is oxidized.
C)Zinc hydroxide is reduced and oxygen is oxidized.
D)Zinc hydroxide is reduced and hydroxide is oxidized.
E)Water is reduced and zinc is oxidized.

Question 67

Radioactive tritium, ³H, is used as a tracer in many biological experiments. It decays by $\beta$ emission. What is the product of this decay?

A)(³He)
B)(⁴He)
C)(²H)
D)(¹⁴C)
E)(²H).

Question 68

Which element may contribute to sudden infant death syndrome (SIDS), as it is used as a fire retardant in mattresses?

A)bismuth
B)chromium
C)boron
D)aluminum
E)antimony

Question 69

Lithium is used in the treatment of which disease?

A)Anemia
B)Alzehimer's
C)Diabetes
D)bipolar disorder
E)multiple sclerosis

Question 70

Pacemakers implanted in the chests of patients with certain heart conditions are powered by a lithium/iodine PVP battery, where PVP represents polyvinylpyridine. The cell reaction and standard cell potential are given below. The standard reduction potential for Li/Li⁺ is -3.05 V. What species is oxidized in this reaction?
$~~~~~~~~$ 3.59 V

A)Li
B)I₂
C)I₂:PVP
D)PVP
E)LiI

Question 71

A patient is injected with a 5.0 $\mu$ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

A)18 hr
B)25 hr
C)32 hr
D)41 hr
E)62 hr

Question 72

The release of radioactive cesium-137 into the environment by the nuclear accident at Chernobyl produced a health hazard because cesium ions can substitute for ________ in plants, making them unsafe for human consumption.

A)Mg²⁺
B)K⁺
C)Ca²⁺
D)Li⁺
E)H⁺

Question 73

The isotope ¹⁸F is used in a range of radio imaging applications. It has a first-order rate constant, k, of 6.30 $\times$ 10^-3 min^-1. What is the half-life for ¹⁸F?

A)159 min
B)110 min
C)9.10 $\times$ 10^-3 min
D)2.34 $\times$ 10^-3 min
E)1,743 min

Question 74

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. Write the balanced reaction equation for the cell and report the sum of the stoichiometric coefficients.
$~~~~~~~~$ -1.249 V $~~~~~~~~$ +0.401 V

A)4
B)5
C)6
D)7
E)8

Question 75

The isotope ²⁰¹Th is used in the diagnosis of heart disease. It has a first-order rate constant, k, of 9.49 $\times$ 10^-3 h^-1. What is the half-life for ²⁰¹Th?

A)73 hr
B)0.014 hr
C)9.49 $\times$ 10^-3 hr
D)7.3 hr
E)1.4 hr

Question 76

A radioactive isotope that emits the shortest range particles and therefore would be a good choice for implantation therapy most likely decays via ________

A)alpha particles.
B)beta particles.
C)positrons.
D)gamma rays.
E)X-rays.

Question 77

The essential elements found in the human body are classified as major, trace, and ultratrace based on their concentration levels. What are the concentration ranges that define each of these classifications?

Question 78

Hearing aid batteries utilize a zinc/air electrochemical cell. The reduction half-reactions and standard reduction potentials for this cell are given below. What is the standard cell potential of a zinc/air cell? $~~~~~~~~$ -1.249 V $~~~~~~~~$ +0.401 V

A)(-0.848 V)
B)(+1.500 V)
C)(+0.848 V)
D)(+1.650 V)
E)(-1.650 V)

Question 79

A patient is injected with a 5.0 $\mu$ M solution of gallium citrate containing radioactive gallium-68 for a PET study. The half-life of gallium-68 is 9.4 hr. How long does it take for the activity of this isotope to drop to 1% of its initial value?

A)18 hr
B)25 hr
C)32 hr
D)41 hr
E)62 hr

Question 80

Calcium is a major essential element in the human body. What is the dominant role played by calcium?