Atoms
Atoms
Preview
• Understanding Concepts
• Reading Skills
• Interpreting Graphics
Standardized Test Prep
Atoms
Standardized Test Prep
Understanding Concepts
1.
When electricity is connected to a neon sign, an atom
of neon inside the sign emits a photon. What has
happened within the atom to allow the emission of light
energy?
A. An electron has moved to a lower energy level.
B. Two electron orbitals have collided.
C. A proton has been lost from the nucleus.
D. The atom has gained a positive charge.
Atoms
Standardized Test Prep
Understanding Concepts
1.
When electricity is connected to a neon sign, an atom
of neon inside the sign emits a photon. What has
happened within the atom to allow the emission of light
energy?
A. An electron has moved to a lower energy level.
B. Two electron orbitals have collided.
C. A proton has been lost from the nucleus.
D. The atom has gained a positive charge.
Atoms
Standardized Test Prep
Understanding Concepts, continued
2. After a single subatomic particle is removed
from an atom of helium, the helium atom
becomes an atom of hydrogen. What subatomic
particle was removed?
F. an electron
G. a proton
H. a quark
I. a neutron
Atoms
Standardized Test Prep
Understanding Concepts, continued
2. After a single subatomic particle is removed
from an atom of helium, the helium atom
becomes an atom of hydrogen. What subatomic
particle was removed?
F. an electron
G. a proton
H. a quark
I. a neutron
Atoms
Standardized Test Prep
Understanding Concepts, continued
3. Gold has an average atomic mass of 196.97 u.
Approximately how many atoms of gold are
there in 100 g of gold? Note: there are
6.022 × 1023 atoms in a mole.
A. 3.0573 × 1019
B. 3.0573 × 1023
C. 1.1862 × 1024
D. 1.1862 × 1028
Atoms
Standardized Test Prep
Understanding Concepts, continued
3. Gold has an average atomic mass of 196.97 u.
Approximately how many atoms of gold are
there in 100 g of gold? Note: there are
6.022 × 1023 atoms in a mole.
A. 3.0573 × 1019
B. 3.0573 × 1023
C. 1.1862 × 1024
D. 1.1862 × 1028
Atoms
Standardized Test Prep
Understanding Concepts, continued
4. What subatomic particles can be found in
regions called orbitals?
F. protons
G. neutrons
H. electrons
I. photons
Atoms
Standardized Test Prep
Understanding Concepts, continued
4. What subatomic particles can be found in
regions called orbitals?
F. protons
G. neutrons
H. electrons
I. photons
Atoms
Standardized Test Prep
Understanding Concepts, continued
5. Xenon has an atomic number of 54. A particular
isotope of xenon has a mass number of 131.
How many protons and how many neutrons
does each atom of that isotope have?
Atoms
Standardized Test Prep
Understanding Concepts, continued
5. Xenon has an atomic number of 54. A
particular isotope of xenon has a mass number
of 131. How many protons and how many
neutrons does each atom of that isotope have?
Answer: 54 protons and 77 neutrons
Atoms
Standardized Test Prep
Understanding Concepts, continued
6. Suppose that a team of chemists discovered
that lead has the following composition: 80% of
lead is an isotope whose mass number is 207,
and 20% of lead is an isotope whose mass
number is 208. What would they determine the
average atomic mass of lead to be?
Atoms
Standardized Test Prep
Understanding Concepts, continued
6. Suppose that a team of chemists discovered
that lead has the following composition: 80% of
lead is an isotope whose mass number is 207,
and 20% of lead is an isotope whose mass
number is 208. What would they determine the
average atomic mass of lead to be?
Answer: 207.2 u
Atoms
Standardized Test Prep
Reading Skills
THE BOHR MODEL OF THE ATOM
In the Bohr model of the atom, electrons can be found
only in certain energy levels. Electrons “jump” directly from
one level to the next level; they are never found between
levels. When an electron moves from one level to another, it
gains or loses energy, depending on the direction of its
jump.
Atoms
Standardized Test Prep
Reading Skills, continued
Bohr’s model explained an unusual event. When
electric charges pass through atoms of a gaseous
element, the gas produces a glowing light, like in a neon
sign. If this light is passed through a prism, a pattern of
lines appears. Each line has a different color. The
pattern depends on the element—neon has one pattern,
and helium has another. In Bohr’s model, the lines are
caused by electron jumps from higher to lower energy
levels. Because only certain jumps are possible,
electrons release energy only in certain quantities.
These “packets” of energy produce the lines that are
seen.
Atoms
Standardized Test Prep
Reading Skills, continued
7. In the Bohr model of the atom, which of the
following characteristics of electrons is limited?
A. the number of electrons in an atom
B. the location of the electrons
C. the size of electrons
D. the speed of electrons
Atoms
Standardized Test Prep
Reading Skills, continued
7. In the Bohr model of the atom, which of the
following characteristics of electrons is limited?
A. the number of electrons in an atom
B. the location of the electrons
C. the size of electrons
D. the speed of electrons
Atoms
Standardized Test Prep
Reading Skills, continued
8. What causes the colored lines that appear
when the light from a gas is passed through a
prism?
F. packets of energy released by electron jumps
G. electrons changing color
H. atoms of the gas exchanging electrons
I. There is not enough information to determine
the answer.
Atoms
Standardized Test Prep
Reading Skills, continued
8. What causes the colored lines that appear
when the light from a gas is passed through a
prism?
F. packets of energy released by electron jumps
G. electrons changing color
H. atoms of the gas exchanging electrons
I. There is not enough information to determine
the answer.
Atoms
Standardized Test Prep
Interpreting Graphics
The graphic below shows how electron orbitals around the nucleus
of an atom are organized into energy levels. Each orbital holds 2
electrons. Use this graphic to answer questions 9–11.
Atoms
Standardized Test Prep
Interpreting Graphics, continued
9. If every orbital of an atom’s n = 4 energy level was full of
electrons, how many electrons would there be in that energy level?
A. 7
C. 16
B. 14
D. 32
Atoms
Standardized Test Prep
Interpreting Graphics, continued
9. If every orbital of an atom’s n = 4 energy level was full of
electrons, how many electrons would there be in that energy level?
A. 7
C. 16
B. 14
D. 32
Atoms
Standardized Test Prep
Interpreting Graphics, continued
10. The atomic number of sulfur is 16. If energy levels are filled
with electrons from the innermost level to the outermost level,
how many electrons are in the n = 3 energy level of a neutral
sulfur atom?
Atoms
Standardized Test Prep
Interpreting Graphics, continued
10. The atomic number of sulfur is 16. If energy levels are filled
with electrons from the innermost level to the outermost level,
how many electrons are in the n = 3 energy level of a neutral
sulfur atom?
Answer: 6 electrons
Atoms
Standardized Test Prep
Interpreting Graphics, continued
11. Every known element has seven or fewer energy levels. How
many orbitals would there be room for in energy level n = 7?
Atoms
Standardized Test Prep
Interpreting Graphics, continued
11. Every known element has seven or fewer energy levels. How
many orbitals would there be room for in energy level n = 7?
Answer: 49 orbitals
Atoms
Standardized Test Prep
Interpreting Graphics, continued
The table below gives information about the subatomic particles in
six atoms. Use this table to answer questions 12–13.
Atoms
Standardized Test Prep
Interpreting Graphics, continued
12. Which two atoms are isotopes of the same element?
F. #1 and #2
H. #3 and #4
G. #2 and #3
I. #4 and #5
Atoms
Standardized Test Prep
Interpreting Graphics, continued
12. Which two atoms are isotopes of the same element?
F. #1 and #2
H. #3 and #4
G. #2 and #3
I. #4 and #5
Atoms
Standardized Test Prep
Interpreting Graphics, continued
13. What is the mass of one mole of the heaviest atom in the table?
Atoms
Standardized Test Prep
Interpreting Graphics, continued
13.
What is the mass of one mole of the heaviest atom in the table?
Answer: 94 grams