9.
a.
Assuming all atoms are neutral, complete the following table:
Isotope
Atomic
Mass
Number of
Number of
Name
Number
Number
Protons
Neutrons
Hydrogen–2
1
2
1
1
1
i
14
29
14
15
14
Te
52
128
52
76
52
Mg
12
24
12
12
12
31
70
31
39
31
b.
c.
128
d.
24
e.
10.
Number of
Electrons
Gallium–70
Write the complete symbol for the ion/atom:
a. 82 protons, 128 neutrons & 82 electrons:
b. 24 protons, 28 neutrons & 18 electrons:
c. 17 protons, 18 neutrons & 18 electrons:
11.
12.
13.
14.
An atom of Element X is 78.60 % of 24X, 10.10 % of 25X, and 11.30 % of 26X.
a. What is the atomic mass of X?
x
x
X – 24.32 amu
x
b. What is the identity of element X?
Mg - Magnesium
c. If the 26X were increased to 70%, would the atomic mass increase? Explain.
 The mass would increase because there is a higher abundance of a
heavier isotope.
Describe alpha, beta, and gamma radiation in terms of symbol, makeup, and strength.
 Alpha – α,
(Helium nucleus), easily stopped
 Beta – β, - - (electron), medium power
 Gamma – γ, high n gy di tion, v y pow f
Complete these nuclear reactions and indicate the type of decay:
a.

+
b.

+
-
(Beta decay)
-
d
(Alpha decay)
Radon-222 has a half-life of 3.8 days. If 136 g of Rn-222 disintegrates over a period of
11.4 days, how many grams will remain?
→
→
→
g