Study Guide
Answer these questions on a separate sheet of paper.
States of matter
 What are the FOUR states of matter?
o Solid, liquid, gas, plasma
 Name the changes between each phase: solid, liquid, and gas.
o Solid  liquid = melting
o Liquid  gas = vaporization
o Gas  solid = deposition
o Solid  gas = sublimation
o Gas  liquid = condensation
o Liquid  solid = freezing
Atoms, Molecules, Compounds, Elements
 What is an atom?
o Smallest unit of matter that retains the properties of its element
 Which term refers to a substance made up of only one type of atom and is identified by an
atomic number?
o Element
 How is a molecule different from a compound?
o A compound is a molecule that contains 2 or more types of atoms (elements). A
molecule is a collection of atoms that may or may not be all the same type (1+
elements). H2O is a compound AND a molecule (made of 2 different elements). O2 is a
molecule, but not a compound (only one type of atom).
 When two different elements react, how are the properties of the product related to the
properties of the starting materials?
o The properties of the product are unrelated to the properties of the starting material(s).
Water (H2O), a liquid at room temperature, can be made from hydrogen and oxygen,
gases at room temperature. Hydrogen is extremely flammable. Oxygen is not
flammable, but is essential for combustion (burning).
Atomic structure
 Name the 3 major subatomic particles. What are their charges?
o Proton (+1), neutron (0), electron (-1)
 An atom has 8 neutrons, 6 protons, and 6 electrons. What is this atom? What determines the
identity of an atom? What is its mass? What is its total charge?
o Carbon
o # protons
o 14 amu (6 protons + 8 neutrons = 14 atomic mass units)
o 0 (neutral; 6 protons – 6 electrons = 0)
 An atom has an atomic mass of 17. If the element is oxygen, how many neutrons must the
nucleus contain?
o 9 (17 – 8 protons = 9 neutrons)
 The outermost ring of electrons is given what name? What is the importance of this ring?
o Valence shell/ring
o
This ring contains the electrons involved in bonding.
Bohr model
 Draw the BOHR model for a magnesium atom. How many energy levels does it have?
3 energy levels
Lewis model
 How many valence electrons does a neutral lithium atom have? What would its charge be as an
ion?
o 1 valence electron
o +1 (lost 1 electron)
Counting atoms
 How many of each type of atom are present in 2 Ca(OH)2?
o Ca: 2
o O: 4
o H: 4
 Why is it important that the same number of atoms be on each side of the reaction?
o The law of conservation of mass states that matter cannot be created nor destroyed.
Therefore, every atom that enters into a reaction must be present at its completion.
Periodic trends
 As you move across the periodic table from left to right, how does the size of atoms change?
o Atoms become smaller, since they hug their electrons closer (higher electronegativity)
 Where are the most electronegative atoms found? What is the relationship between
electronegativity and atomic size?
o The most electronegative atoms are in the top right-hand corner of the periodic table (F,
Cl, O, etc.)
o As electronegativity increases, size decreases (and vice versa)
 All the alkali metals have reactions with water, increasing in intensity as you move down the
periodic table. What does this say about the properties of elements in the same group?
o Elements in the same group share some properties, especially reactivity (since each
element will have the same number of valence electrons – the electrons responsible for
reactivity and bonding).
 Be sure you can identify the different groups (halogens, noble gases, alkali metals, etc.) on a
periodic table (NOT your personal table).
Ionic bonding
 What would the charges of the following atoms be during ionic bonding?
o Ca
 +2
o N
 -3
o O
 -2
o Na
 +1
o Ba
 +2
Covalent bonding
 How are covalent bonds formed (electronically speaking)? As a result, do the atoms involved
have charges?
o Covalent bonds are formed by two atoms sharing a pair of electrons. Each atom
contributes one electron to the pair, and each atom counts the pair of electrons as its
own.
o Atoms involved in covalent bonding do not have charges, since no electrons are actually
joining/leaving the atom.
Types of bonds
 Determine the type of bond that would form between the two kinds of atoms.
o Ag, F
 ionic
o S, O
 covalent
o C, H
 covalent
o Pt, Sn
 metallic
o Fe, Cl
 ionic
Balancing chemical equations
 ____ Na3PO4 + ____ KOH  ____ NaOH + ____ K3PO4
o 1, 3, 3, 1
 ____ MgF2 + ____ K  ____ KF + ____ Mg
o 1, 2, 2, 1
 ____ C2H6 + ____ O2  ____ CO2 + ____ H2O
o 2, 7, 4, 6
Physical/Chemical Properties
 For each property, indicate whether it is a physical or chemical property.
o Density
 physical
o
o
o
o
o
o
pH
 chemical
reactivity
 chemical
volume
 physical
hardness
 physical
odor
 physical
flammability
 chemical
Physical/Chemical Changes
 What is the difference between a physical and chemical change?
o Physical changes do not affect the nature of the material (you have the same compound
before and after the change – tearing paper gives two new pieces of paper, but they’re
still paper). Chemical changes alter the material, creating a new compound (burning
paper turns the cellulose fibers into carbon dioxide and water).
 What are 3 indicators that a chemical change might be happening?
o Color change
o Odor change
o Temperature change
o Formation of gas
o Formation of precipitate (solid)
o Light emitted
 Chemical changes can be endothermic or exothermic. What is the difference?
o Endothermic reactions take energy in, resulting in a reaction that feels cold (citric acid
and baking soda). Exothermic reactions give energy off, resulting in reactions that feel
hot (burning paper).