Matter and Its Changes
The Periodic Table
1. Atomic number is equal to what?
2. How are elements arranged in the periodic table?
3. How many electrons does helium have? How do you know?
4. Would you expect lithium and potassium to have similar qualities? Why or why not?
5. How do you figure out how many neutrons an element has?
6. What is an ion?
Matter
Use the words or statements below to complete the concept map. Pay particular attention to the
linking words or statements between boxes. The completed diagram will help you organize the
relationships between physical states of matter on Earth.







Liquid
Definite size and shape
Gas
Water
Freely moving and independent
Takes the shape of its container
Water
Matter and Its Changes
In the blank at the left, write the letter of the term that best completes each statement.
__________ 1. _____________ are the basic units of matter.
a. Electrons
b. Molecules
c. Atoms
d. Spaces
__________ 2. _____________ are particles without an electrical charge in the atom’s nucleus.
a. Neutrons
b. Electrons
c. Ions
d. Protons
__________ 3. When nuclear fission is used, an atomic chain reaction releases _________________.
a. water
b. heat
c. radioactivity
d. uranium
__________ 4. Hydrogen-1 and hydrogen-2 are _______________ of one another.
a. ions
b. conductors
c. isotopes
d. compounds
__________ 5. The density of a substance is a _________________ of the substance.
a. state of matter
b. physical property c. solution
d. chemical property
__________ 6. Anything that takes up space and has mass is _____________.
a. a compound
b. an element
c. matter
d. plasma
__________ 7. Tea with sugar is an example of a(n) ______________.
a. Mixture
b. gas
c. compound
d. element
__________ 8. A positively charged ______________ has more protons than electrons.
a. ion
b. isotope
c. neutron
d. molecule
__________ 9. Isotopes of carbon have different _______________.
a. numbers of electrons
b. atomic numbers
c. mass numbers
d. numbers of protons
__________ 10. _______________ are particles located in an atom’s nucleus.
a. Electrons and neutrons
c. Protons and electrons
b. Only electrons
d. protons and neutrons
__________ 11. On Earth, water is naturally found in all of these states except ____________.
a. gas
b. liquid
c. solid
d. plasma
__________ 12. At its boiling point, a liquid becomes a ________________.
a. gas
b. liquid
c. solid
d. plasma
__________ 13. State of matter can be changed by ___________ or temperature.
a. weight
b. density
c. pressure
d. observation
__________ 14. H2O is a compound formed by sharing ___________.
a. neutrons
b. electrons
c. ions
d. protons
__________ 15. Two or more elements whose atoms are chemically bonded form a(n) _______.
a. Mixture
b. ion
c. nucleus
d. compound
Using the underlined word, identify whether each statement is true or false. Rewrite false
statements by changing the underlined word to make it correct.
________ 16. A substance with greater density than water will sink in water.
________________________________________________
________ 17. Fission is the joining of nuclei of atoms to form heavy elements such as uranium.
________________________________________________
________ 18. One chemical property of a substance is its density.
________________________________________________
________ 19. A substance that expands to completely fill a container is a liquid.
________________________________________________
________ 20. A proton is a positively charged particle in an atom’s nucleus.
________________________________________________
If the statement or term identifies a compound, list its number under “compound.” If it
identifies a mixture, list its number under “mixture.”
Compound
Mixture
______________
______________
______________
______________
______________
______________
______________
______________
______________
______________
21. Its components can be separated by physical means.
22. It has properties that differ from those of its separate elements.
23. A solution
24. H2O or NaCl
25. It can be formed by atoms sharing electrons or by negative and positive ions joining.
26. Oil and vinegar.
27. It is made up of two or more compounds.
28. Molecules are it building blocks.
29. It requires a chemical change to be separated.
30. Its components keep their own properties.
Understanding Concepts
Complete the table. Then use the table to answer the questions.
Atom
A
Number of
Number of
Number of
Atomic
Mass
protons
neutrons
electrons
number
number
6
B
C
0
11
D
17
F
12
1
12
1
10
8
E
G
6
6
23
6
18
12
12
10
10
35
9
1. Which of the two substances are isotopes of one another? Explain why they are
isotopes.
2. Identify the particles that are ions and tell how you know they are ions.
3. Identify the positively charged ion and explain why its charge is positive.
4. Which atom could combine with atom E to form a compound? Explain why they could
combine.
5. Can atoms E and G combine to form a compound? Explain.
Combination of Atoms
Define the following terms.
1. Compound_______________________________________________________________
_______________________________________________________________________
2. Mixture_________________________________________________________________
________________________________________________________________________
Identify each of the following as a mixture or compound
3. H2O
_____________________________
4. Solution
_____________________________
5. NaCl
_____________________________
6. Salt water
_____________________________
7. Salt
_____________________________
8. Water
_____________________________
9. NaCl + H2O
_____________________________
10. Air
_____________________________
11. Vinegar and oil
_____________________________
Complete the following sentences.
12. A water molecule is made up of two atoms of _______________________ and one atom
of ____________________________.
13. Table salt is made up of one ion of _______________________ and one ion of
____________________________.
14. The substances in a(n) ______________________ can be physically separated from one
another.
15. Sweetened tea is a type of mixture called a(n) ___________________________.
16. A(n) __________________________ cannot be separated into its individual elements by
physical means.
Chemical Formulas
Chemical formula: Shorthand way of writing a compound.
Each element has its own chemical symbol. Each compound has its own chemical formula. A
formula tells us two important things about a compound. It tells us what elements the
compound is made of. It also tells us how many atoms of each element are in a molecule of the
compound.
The formula for table salt is NaCl…

Na is the symbol for sodium

Cl is the symbol for chlorine
One molecule of NaCl has a total of two atoms. One of the atoms is sodium (Na). The other is
chlorine (Cl).
Sometimes a symbol has a small number written next to it. This number tells us the number of
atoms there are of that element.
The formula for water is H2O …

H is the symbol for hydrogen.

O is the symbol for oxygen.

H2 means two atoms of hydrogen.

O means one atom of oxygen because the symbol
Stand for 1 atom of the element.
One molecule of H2O then, has a total of three atoms. Two of the atoms are hydrogen. One
atom is oxygen.
The formula for a compound is always the same. A change in the formula means a new
substance was formed.
Some Common Molecules
Formula: HgO
Name: Mercuric oxide
Elements: mercury (Hg) and oxygen (O)
Number of atoms in each element:
1 atom of mercury (Hg)
1 atom of oxygen (O)
Total number of atoms in one molecule: 2 atoms total
Formula: H2SO4
Name: Sulfuric acid
Elements: Hydrogen (H), Sulfur (S), oxygen (O)
Number of atoms in each element:
2 atoms of hydrogen (H)
1 atom of sulfur (S)
4 atom of oxygen (O)
Total number of atoms in one molecule: 7 atoms total
Choose the correct word for each statement. Write your choice on the line.
1. A molecule is made up of _____________________________.
(atoms, oxygen)
2. A single molecule has at least ______________________ atoms.
(one, two)
3. ______________________ are combined to make __________________________.
(Elements, Compounds)
(elements, compounds)
4. There are _____________________ elements than compounds.
(more, fewer)
The formula for starch is C6H10O5. This stands for one molecule of starch. Answer the following
questions about the starch molecule.
5. Starch is made up of ___________________ elements.
(one, two, three)
6. The total number of atoms in one molecule of starch is ________________.
(6, 10, 16, 21)
7. The number of different kinds of atoms in starch is ________________.
(1, 3, 16, 21)
Given the name of the elements and the number of atoms of each, you can write
the formula for a compound.
Compounds name
Elements and how many of each
Formula
Sand
1 atom of silicon, 2 atoms of oxygen
SiO2
Borax
2 atoms of sodium, 4 atoms of boron, 7
atoms of oxygen
Moth balls
10 atoms of carbon, 8 atoms of hydrogen
Smelling salts
1 atom of nitrogen, 4 atoms of hydrogen, 1
atom of oxygen, 1 atom of hydrogen
Chalk
1 atom of calcium, 2 atoms of carbon, 3
atoms of oxygen
Hydrogen peroxide
2 atoms of hydrogen, 2 atoms of oxygen
Table salt
1 atom of sodium, 1 atom of chlorine
Nitric acid
1 atom of nitrogen, 1 atom of nitrogen, 3
atoms of oxygen
Starch
6 atoms of carbon, 10 atoms of hydrogen, 5
atoms of oxygen
Propane
3 atoms of carbon, 8 atoms of hydrogen
Vinegar
1 atom of hydrogen, 2 atoms of carbon, 3
atoms of hydrogen, 2 atoms of oxygen
Sugar
12 atoms of carbon, 22 atoms of hydrogen,
11 atoms of oxygen
Natural Gas
1 atom of carbon, 4 atoms of hydrogen
Baking soda
1 atom of sodium, 1 atom of hydrogen, 1
atom of carbon, 3 atoms of oxygen
Complete the chart
Formula
MgO
Name
Magnesium
oxide
SO2
Sulfur dioxide
NH4
Ammonia
H2CO3
Carbonic acid
(soda pop)
KClO3
Potassium
Chlorate
MgSO4
Epsom salts
NaOH
Sodium
Hydroxide (lye)
H2O2
Hydrogen
peroxide
Fe2O3
Iron oxide (rust)
AgNO3
Silver nitrate
CUCl2
Copper Chloride
HCl
Hydrochloric
acid
NH4NO3
Ammonium
nitrate
NaHCO3
Sodium
bicarbonate
Number of
Name of the
Number of
Total number of
elements
elements
atoms of
atoms in one
each element
molecule
Magnesium
1
2
oxygen
1
2