Download Isotopes and relative weight review sheet

Name_______________________________ period____Isotopes and relative weight review
worksheet
1. Complete the following table.
Element
Symbol # of protons # of electrons
Molybdenum
mass number # of neutrons
96
Kr
48
14
28
Hg+
121
2. Complete the following tables.
Subatomic Particle
Charge(+,-, neutral)
Location in the atom
Proton
Neutron
Electron
3. Put the people (or atomic theory) listed below in the correct chronological order and describe
how our 'picture' of the atom changed with each.
A. Dalton
B. Rutherford
C. Bohr
D. Modern
E. Thomson
8.Match the following historic scientist with the experiment, discovery or contribution to our
understanding of atomic structure. Use the following choices: Dalton (D), J.J. Thompson (T),
Ernest Rutherford (R), Neils Bohr (B), Modern Quantum View (MQV).
_____a. Developed the plum-pudding model of the atom.
_____b. First person to develop a nuclear model of the atom.
_____c. First person credited with providing emperical evidence for the existence of atoms.
_____d. Proposes that the precise location and energy of an electron can not be simultaneously
known.
_____e. Bombarded gold foil with alpha particles and observed scattering.
_____f. Proposed the existence of orbitals - regions of space having a high probability of an
electron being located in it.
_____g. Suggested that electrons orbit the nucleus in fixed paths with quantized energy levels.
_____h. Experimented with cathode rays and discovered the existence of the electron.
Elements and Their Isotopes
Part of Atom
proton
neutron
electron
Charge
+1
0
-1
Atomic weight (u)
1.0073
1.0087
0.000549
Because electrons weigh so little we do not count them
when figuring out the weight of an atom or an isotope.
Only the proton and neutron are used.
1. The common form of helium gas (the gas often put in balloons) is called helium-4.
a. The number of protons in any atom is the same as its atomic number. What is the
atomic number of helium? _____
b. How many protons does helium have? _____
c. Helium has two neutrons, plus the number of protons you determined. Find the total
atomic weight of helium-4.
d. Why do you think helium-4 is called helium-4?
2. The common form of iodine (the liquid that is often put on cuts and wounds) is called
iodine-126.
a. The number of protons in any atom is the same as its atomic number. What is the
atomic number of iodine? _____ Therefore iodine has ____ protons.
c. Iodine has 73 neutrons, plus the number of protons you determined. Find the total
atomic weight of iodine-126. Show your calculations.
d. Why do you think iodine-126 is called iodine-126?
3. The common form of uranium (a metal used in nuclear reactors) is called uranium-238.
a. The number of protons in any atom is the same as its atomic number. The atomic
number of uranium is _____. Therefore uranium has _____ protons.
b. Uranium has 146 neutrons, plus the number of protons you determined. Find the total
atomic weight of uranium-238. Show your calculations.