chapter 2 atoms and elements

Chapter 2

Atoms and Elements

Clicker Questions

Allison SoultUniversity of Kentucky

Two samples of the same compound are compared:

Sample 1: 24.22 g carbon and 32.00 g oxygen Sample 2: 36.22 g carbon and 48.00 g oxygen

This data shows which of the following?

a) The law of definite proportions

b) The law of multiple proportions

c) The law of conservation of mass

d) a and b only

e) a, b, and c

Two samples of the same compound are compared:

Sample 1: 24.22 g carbon and 32.00 g oxygen Sample 2: 36.22 g carbon and 48.00 g oxygen

This data shows which of the following?

a) The law of definite proportions

b) The law of multiple proportions

c) The law of conservation of mass

d) a and b only

e) a, b, and c

What information about atomic structure was determined by Millikan’s oil drop experiment?

a) Presence of electrons

b) Presence of nucleus

c) Charge on an electron

d) Charge on a neutron

e) Charge on a proton

What information about atomic structure was determined by Millikan’s oil drop experiment?

a) Presence of electrons

b) Presence of nucleus

c) Charge on an electron

d) Charge on a neutron

e) Charge on a proton

Which of the following statements about a carbon atom is correct according to the plum-pudding atom model?

a) Nothing can penetrate acarbon atom.

b) The carbon atom has apositive charge.

c) The positive charge isdistributed over thesphere of the atom.

d) The carbon atom has anegative charge.

Which of the following statements about a carbon atom is correct according to the plum-pudding atom model?

a) Nothing can penetrate acarbon atom.

b) The carbon atom has apositive charge.

c) The positive charge isdistributed over thesphere of the atom.

d) The carbon atom has anegative charge.

Which scientist confirmed that most of an atom’s mass and all of its positive charge are contained in a small core called the nucleus?

a) John Dalton

b) Joseph Proust

c) J. J. Thomson

d) Ernest Rutherford

e) Robert Milliakn

Which scientist confirmed that most of an atom’s mass and all of its positive charge are contained in a small core called the nucleus?

a) John Dalton

b) Joseph Proust

c) J. J. Thomson

d) Ernest Rutherford

e) Robert Milliakn

Which of the following determines the identity ofan atom?

a) Number of protons

b) Number of electrons

c) Number of neutrons

d) Total number of protons and neutrons

e) Total number of protons and electrons

Which of the following determines the identity ofan atom?

a) Number of protons

b) Number of electrons

c) Number of neutrons

d) Total number of protons and neutrons

e) Total number of protons and electrons

How many neutrons are in 1000 atoms of Cl-37?

b) 37,000

d) 20,000

e) Cannot be determined

How many neutrons are in 1000 atoms of Cl-37?

b) 37,000

d) 20,000

e) Cannot be determined

How many protons are in an atom of 195Pt?

a) 273

b) 195

c) 117

How many protons are in an atom of 195Pt?

a) 273

b) 195

c) 117

Which of the following statements is true about ions?

a) An ion is the result of an atom gaining a neutron.

b) A positively charged ion results from the gain ofa proton.

c) A negatively charged ion results from the loss ofa proton.

d) The gain or loss of an electron by an atom willresult in an ion.

e) None of the above.

Which of the following statements is true about ions?

a) An ion is the result of an atom gaining a neutron.

b) A positively charged ion results from the gain ofa proton.

c) A negatively charged ion results from the loss ofa proton.

d) The gain or loss of an electron by an atom willresult in an ion.

e) None of the above.

To form an ion, aluminum is most likely to

a) gain three electrons to become Al3–.

b) lose three electrons to become Al3+.

c) gain three protons to become Al3+.

d) lose three protons to become Al3–.

To form an ion, aluminum is most likely to

a) gain three electrons to become Al3–.

b) lose three electrons to become Al3+.

c) gain three protons to become Al3+.

d) lose three protons to become Al3–.

If a pure copper penny has 2.94 × 1022 atoms, what will be its mass?

a) 1.30 g

b) 0.323 g

c) 2.79 g

d) 3.10 g

e) 1.12 g

If a pure copper penny has 2.94 × 1022 atoms, what will be its mass?

a) 1.30 g

b) 0.323 g

c) 2.79 g

d) 3.10 g

e) 1.12 g

Which of the following elements is an alkaliearth metal?

Which of the following elements will have properties most similar to tin, Sn (50)?

a) Lead, Pb (82)

b) Gallium, Ga (31)

c) Zinc, Zn (30)

d) Titanium, Ti (22)

e) Arsenic, As (33)

Which of the following elements will have properties most similar to tin, Sn (50)?

a) Lead, Pb (82)

b) Gallium, Ga (31)

c) Zinc, Zn (30)

d) Titanium, Ti (22)

e) Arsenic, As (33)

metal metal

very malleable very malleable

SnO, SnO2 PbO, PbO2

SnCl2, SnCl4 PbCl2, PbCl4

Boron has two naturally occurring isotopes:B-10 with an isotopic mass of 10.013 amuB-11 with an isotopic mass of 11.009 amu

Calculate the percent abundance for each isotope if the average atomic mass of boron is 10.81 amu.

a) 50.0% B-10, 50.0% B-11

b) 25.0% B-10, 75.0% B-11

c) 19.8% B-10, 80.2% B-11

d) 26.4% B-10, 73.6% B-11

e) Not enough information to determine

Boron has two naturally occurring isotopes:B-10 with an isotopic mass of 10.013 amuB-11 with an isotopic mass of 11.009 amu

Calculate the percent abundance for each isotope if the average atomic mass of boron is 10.81 amu.

a) 50.0% B-10, 50.0% B-11

b) 25.0% B-10, 75.0% B-11

c) 19.8% B-10, 80.2% B-11

d) 26.4% B-10, 73.6% B-11

e) Not enough information to determine

The mass spectrum of gallium, Ga, is shown as follows. The atomic mass of Ga is 69.7 amu. Whichof the following statements is correct?

a) All Ga atoms weigh69.7 amu.

b) The atomic mass ofGa is the average of68.9 and 71.9.

c) The atomic mass of Gawill be closer to 69 than71 because there aremore atoms that weigh68.9 amu.

The mass spectrum of gallium, Ga, is shown as follows. The atomic mass of Ga is 69.7 amu. Whichof the following statements is correct?

a) All Ga atoms weigh69.7 amu.

b) The atomic mass ofGa is the average of68.9 and 71.9.

c) The atomic mass of Gawill be closer to 69 than71 because there aremore atoms that weigh68.9 amu.

Which of the following is FALSE?

a) The mole can be used to specify Avogadro’s numberof anything.

b) Avogadro’s number, 6.022 × 1023, is an exactnumber.

c) The mole is equal to the number of atoms in exactly12 grams of carbon-12.

d) The value of an element’s molar mass in grams per mole is numerically equal to the element’s atomicmass in amu.

Which of the following is FALSE?

a) The mole can be used to specify Avogadro’s numberof anything.

b) Avogadro’s number, 6.022 × 1023, is an exactnumber.

c) The mole is equal to the number of atoms in exactly12 grams of carbon-12.

d) The value of an element’s molar mass in grams per mole is numerically equal to the element’s atomicmass in amu.

Which has more atoms, 10.0 g Mg or 10.0 g Ca?

a) Magnesium

b) Calcium

c) Both have the same number of atoms.

Which has more atoms, 10.0 g Mg or 10.0 g Ca?

a) Magnesium

b) Calcium

c) Both have the same number of atoms.

Calculate the mass in grams of one mole of footballs if one football has a mass of 0.43 kg.

a) 430 g

b) 1.4 g

c) 2.6 × 1026 g

d) 7.1 × 10–23 g

e) 1.4 × 1027 g

Calculate the mass in grams of one mole of footballs if one football has a mass of 0.43 kg.

a) 430 g

b) 1.4 g

c) 2.6 × 1026 g

d) 7.1 × 10–23 g

e) 1.4 × 1027 g

Which of the following has the largest mass?

a) 10.0 g Li

b) 10.0 moles of Li

c) 100 g Na

d) 10.0 moles of K

e) 100 g Rb