Transcript Slide 1

Chemistry: A Molecular Approach, 1st Edition
Nivaldo J. Tro
Chapter 2
Atoms and
Elements
Which of the following statements about a carbon atom
is correct according to the plum-pudding atom model?
a) Nothing can penetrate a
carbon atom.
b) The carbon atom has a
positive charge.
c) The mass of the carbon atom
is the same as the mass of all
the electrons in the atom.
d) The carbon atom has a
negative charge.
Which of the following statements about a carbon atom
is correct according to the plum-pudding atom model?
a) Nothing can penetrate a
carbon atom.
b) The carbon atom has a
positive charge.
c) The mass of the carbon atom
is the same as the mass of all
the electrons in the atom.
d) The carbon atom has a
negative charge.
How many neutrons are in 1000
atoms of Cl-37?
a)
b)
c)
d)
e)
37
37,000
20
20,000
cannot be determined
How many neutrons are in 1000
atoms of Cl-37?
a)
b)
c)
d)
e)
37
37,000
20
20,000
cannot be determined
The mass spectrum of gallium, Ga, is shown below. The atomic mass
of Ga is 69.7 amu. Which of the following statements is correct?
a) All Ga atoms weigh 69.7 amu.
b) The atomic mass of Ga is the
average of 68.9 and 71.9.
c) The atomic mass of Ga will
be closer to 69 than 71
because there are more atoms
that weigh 68.9 amu.
Relative Abundance (%)
Gallium Mass Spectrum
70
68.9 amu, 60.1 %
60
50
71.9 amu, 39.9 %
40
30
20
10
0
67
68
69
70
Mass (amu)
71
72
The mass spectrum of gallium, Ga, is shown below. The atomic mass
of Ga is 69.7 amu. Which of the following statements is correct?
a) All Ga atoms weigh 69.7 amu.
b) The atomic mass of Ga is the
average of 68.9 and 71.9.
c) The atomic mass of Ga will
be closer to 69 than 71
because there are more
atoms that weigh 68.9 amu.
Relative Abundance (%)
Gallium Mass Spectrum
70
68.9 amu, 60.1 %
60
50
71.9 amu, 39.9 %
40
30
20
10
0
67
68
69
70
Mass (amu)
71
72
Which of the following elements will have properties
most similar to Tin, Sn (at. no. 49)?
a)
b)
c)
d)
e)
lead, Pb (82)
gallium, Ga (31)
zinc, Zn (30)
titanium, Ti (22)
arsenic, As (33)
Which of the following elements will have properties
most similar to Tin, Sn (49)?
a)
b)
c)
d)
e)
lead, Pb (82)
gallium, Ga (31)
zinc, Zn (30)
titanium, Ti (22)
arsenic, As (33)
Sn
Pb
metal
metal
very malleable
very malleable
SnO, SnO2
PbO, PbO2
SnCl2, SnCl4
PbCl2, PbCl4
Which weighs more, a pea or a marble?
a) Pea
b) Marble
Tro Chemistry: A Molecular Approach
Which weighs more, a pea or a marble?
a) Pea
b) Marble
Tro Chemistry: A Molecular Approach
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.
24.30
40.08
Tro Chemistry: A Molecular Approach
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.
24.30
40.08
Tro Chemistry: A Molecular Approach