Download Chapter 18 Comparing Atoms Lab

Unit 6—Properties of Matter
Chapter 18: Atoms and Elements
Name_________________________
Lab 18.2—Comparing Atoms
In this investigation, you will investigate the structure of the atom and identify what makes atoms of
different elements different from each other.
We once believed that atoms were the smallest unit of matter. Then it was discovered that there are
even smaller particles inside atoms (J.J. Thomson). The structure of the atom explains why nearly all the
properties of matter we experience are what they are. This investigation will lead you through some
challenging and fun games that illustrate how atoms are built from protons, neutrons, and electrons.
In this investigation, you will use the atom board game to learn about atomic structure. The marbles
will represent the three particles in the atom. Red marbles are protons, blue marbles on neutrons, and
yellow marbles are electrons. The position of the marbles on the board shows where the real particles
are in the atom. The neutrons and protons are in the nucleus (center) and the electrons are arranged in
energy levels around the outside.
6,7
Li
3
Lithium
Mass Number—The mass number is the total number of particles (protons plus
neutrons) in the nucleus. Atoms with the same number of protons but different
mass numbers are called isotopes. These numbers are the mass numbers of the
stable isotopes. Stable isotopes are not radioactive. For example, lithium has
two stable isotopes, Li6 with three protons and three neutrons, and Li7 with three
protons and four neutrons.
Element Symbol
Atomic number—The atomic number is the number of protons in the nucleus.
The atomic number determines what element the atom is. All atoms of a given
element have the same atomic number. For example, all atoms of lithium (Li)
have 3 protons in the nucleus.
Procedure/Data/Results:
1. Using the atom game board and the correctly colored marbles, build an atom of lithium-6.
2. Using the mass number periodic table provided, answer each of the following:
a. What is the number below the element symbol? What does this number tell you about the
atom?
b. What is(are) the number(s) above the element symbol called? What does this tell you about
the atom?
c. Why do some elements have more than one number above the symbol? What are the
variations in this number called?
Unit 6—Properties of Matter
Chapter 18: Atoms and Elements
3.
Build the six atoms shown in the chart on the next page and fill in the missing information.
Protons and neutrons go in the middle of the board. Electrons go in the outside and fill up the
holes from the lowest row (closest to nucleus) to the highest (furthest from the nucleus).
3a.
Element
Atomic Number
Mass Number
Protons
4
Neutrons
5
3b.
6
6
3c.
3d.
Electrons
7
8
8
3e.
3f.
6
10
27
10
10
13
4. Two of the atoms you made were the same element. What was different about them?
5. One of the atoms had just enough electrons to completely fill the first two rows. Which atom
was this? Where on the periodic table is it found?
6. What atom had an atomic number of 8?
7. Which atom had a mass number of 13?
8. One atom is found in a lightweight, silvery metal used in airplanes. Which atom is it?
9. One atom represents an element that makes up about 21% of the Earth’s atmosphere. Which
atom is it?
10. Playing the game of atomic Challenge. Each player takes a turn adding protons, neutrons, and
electrons to the atom to build heavier and heavier elements. The winner is the first player to
run completely out of marbles. Play a few games until everyone in your group is proficient.
a. Each player should start with 6 blue (neutrons), 5 red (protons), and 5 yellow (electrons)
marbles.
b. Each player takes a turn add 1-5 marbles, but not more than 5. The marbles may include
any mixture of electrons, protons, and neutrons. For example, you can add one blue, one
red, and one yellow marble in a turn. That makes 3 total marbles which is less than 5.
c. Marbles played in a turn are added to the marbles already in the atom.
d. Only atoms where the electrons, protons, and neutrons match one of the naturally
occurring elements on the mass number periodic table are allowed. If you add marbles that
make an atom NOT on the periodic table you have to take your marbles back and try again.
Unit 6—Properties of Matter
Chapter 18: Atoms and Elements
The Three Rules:
Rule #1—The number of protons matches the atomic number.
Rule #2—The total number of protons and neutrons equals a stable
mass number.
Rule #3—The number of electrons matches the number of protons.
e. A player can trade marbles with the bank INSTEAD of taking a turn. The player can take as
many marbles, and of as many colors as they need but must take at least as many total
marbles as they put in. For example, a player can trade 2 yellows for 1 yellow, 1 blue, and 1
red.
11. Which particles are found in an atom’s nucleus? Which particles are found outside the nucleus?
12. What four elements make up almost all of the mass in your body?
13. What is the atomic number of sodium?
14. How many protons does sodium have?
15. How many stable isotopes does oxygen have?
16. Name one element that is always radioactive and has an atomic number less than 50.
17. Find and list here the name and symbol of three additional elements that have no stable
isotopes.
18. What element has 26 protons in its nucleus?
19. How many different isotopes does magnesium have?
20. How many protons, neutrons, and electrons does Mg26 have?
21. If an isotope of silicon has 15 neutrons, what is its mass number?
22. What is the heaviest element with at least one isotope that is NOT radioactive?
23. On most periodic tables, a single atomic mass is listed instead of the mass numbers for all the
stable isotopes. How is this mass related to the different isotopes?