How many protons, neutrons, and electrons are in each of the
following?
(a)
an oxygen atom with a mass number of 15
2.33
(b)
a silver atom with a mass number of 109
(c)
a chlorine atom with a mass number of 35
How many protons, neutrons, and electrons are in each of the
following?
(a)
a hydrogen atom with a mass number of 1
2.34
(b)
a magnesium atom with a mass number of 26
(c)
a lithium atom with a mass number of 6
2.35
What is the isotope symbol for atoms that contain the following
numbers of subatomic particles?
(a)
1 proton, 1 electron, and 2 neutrons
(b)
4 protons, 4 electrons, and 5 neutrons
(c)
15 protons, 15 electrons, and 16 neutrons
What is the isotope symbol for atoms that contain the following
numbers of subatomic particles?
(a)
2 protons and 1 neutron
(b)
47 protons and 62 neutrons
(c)
82 protons and 125 neutrons
2.36
What forms when a neutral atom undergoes each of the
following changes?
(a) It gains one electron.
(b) It loses two electrons.
2.41 What forms when an ion with a 1+ charge undergoes each of
the following changes?
2.40
It gains one electron.
(b) It loses two electrons.
(a)
2.52
Complete the following table for the designated ions.
Isotope
Symbol
Number of Number of Number of
Protons
Neutrons Electrons
81 −
35Br
1H+
38
50
36
1
1
2
2.52
2.53
2.54
What element has 18 electrons when it forms an anion with a 2−
charge?
What element has 27 electrons when it forms a cation with a 2+
charge?
What element has 46 electrons when it forms a cation with a 1+
charge?
2.55
An unknown element (X) discovered on a planet in another
galaxy was found to exist as two isotopes. Their atomic
masses and percent abundances are listed in the following
table. What is the relative atomic mass of the element?
Isotope
Mass (amu)
Natural
Abundance
(%)
22X
21.995
75.00
20X
19.996
25.00
2.56
Suppose that the isotope abundance of magnesium on another planet has
been determined to be different from that on Earth, as shown in the
following table. Calculate the relative atomic mass of magnesium on this
planet.
Isotope
24Mg
25Mg
26Mg
Mass (amu)
23.985
24.985
25.983
Natural
Abundance (%)
20.00
20.00
60.00
2.81
Name the element that is an alkaline earth metal in period 5.
2.82
What element is in group IVB (4) and in period 4?
2.83
What element is in group IVA (14) and in period 2?
Identify each of the following elements as a metal, nonmetal, or
metalloid.
(a) calcium
(b) carbon
(c) potassium
(d) silicon
2.84
For each element listed, write the symbol for the ion it forms.
(a) sodium
(b) oxygen
(c) sulfur
(d) chlorine
(e) bromine
2.85
For each element listed, write the symbol for the ion it forms.
(a) nitrogen
(b) phosphorus
(c) magnesium
(d) potassium
(e) aluminum
2.86