2nd Six Weeks Test Topics
Everything and anything we covered since the first day of school could be the topic of a question on this exam. This
exam is intended to be cumulative of all topics we have addressed this school year in science.
Week 1- Safety

Safety gear-goggles, apron, gloves

Safety equipment-fire extinguisher, emergency eyewash, fire blanket

P.A.S.S. –pull, aim, squeeze, sweep

Safety drills-Shelter in place, fire,tornado

Tetrahedron of Fire-heat, oxygen, fuel, and uninterrupted chain reaction

3 Stages of Fire- ignition, smoke, flame

Safety procedures for conducting labs-Wear safety gear. Tell teacher first if anything is wrong!! Wash hands
last. Follow all instructions. Wait for instructions. Clean up after yourself. Never use damaged lab ware. Ask
questions. No horseplay!
Weeks 2-6- Structure of Atoms/Periodic Table

2 regions-nucleus and electron cloud

nucleus- contains protons and neutrons

electron cloud-contains electrons

electrical charges of subatomic particles: protons-positive; neutrons-neutral; electrons-negative

masses of subatomic particles: in order from greatest to least—neutrons, protons, electrons

atomic mass unit(amu)-protons and neutrons each have 1amu; electrons are not assigned an amu

most mass of an atom is in the nucleus

most volume of an atom is in the electron cloud

most volume of an atom is empty space

atomic number is equal to number of protons in nucleus

identity of an atom is defined by its atomic number

atomic mass is equal to number of protons and neutrons added together

a neutral atom has an equal number of protons and electrons

to find the electrical charge of an atom; add together the protons (+) and the electrons (-)

an atom with an electrical charge does not have an equal number of protons and electrons

an ion is an atom with an electrical charge

an isotope of an element has a different number of neutrons, but is still the same element. For example, carbon
12 has 6 protons and 6 neutrons, whereas carbon 14 has 6 protons and 8 neutrons. They are both carbon, but
are called isotopes of carbon.

the electron cloud has up to 7 energy levels

the first energy level holds up to 2 electrons; the second-fourth energy levels will be full if there are 8 electrons
in each shell (octet rule and duet rule)

valence electrons are those found in the outer energy shell

a molecule is made of 2 or more atoms chemically bonded together

a compound is made of 2 or more different elements chemically bonded together

Formation of compounds: atoms that share electrons have a covalent bond

Formation of compounds: atoms that give up or take in electron form ionic bonds

Periodic Table of the Elements is organized by atomic number increasing sequentially by one

Periodic Table rows-horizontal-are called periods

Periodic Table columns-vertical-are called groups or families

7 periods, each with the same number of energy levels

18 groups, each have similar chemical properties and same number of valence electrons

Group 18, or 8A contains the noble gases

noble gases all have full valence shells and are nonreactive

Group 1, or 1A contains alkali metals

Group 2, or 2A contains alkaline earth metals

Group 17, or 7A contains the most reactive elements (the salt formers)

Groups 1A and 7A combine to form compounds readily to satisfy the octet rule

metals are found on left

nonmetals are found on right

metalloids are found in-between along the stair step line

know the properties of metals, nonmetals, and metalloids

know the trends of the Periodic Table pertaining to metallic properties and atomic size
Weeks 7-12 Chemical Formulas, Chemical Equations, Chemical Reactions

A chemical symbol has one or two letters that stands for an element. If the symbol requires two letters, the first
letter is capitalized and the second letter is lower case. Examples: O stands for oxygen. He stands for helium.

A chemical formula tells which elements and how many atoms of each element are found in one molecule of a
compound or one molecule of an element. Examples: H2O is the chemical formula for water, a compound. Each
water molecule has 2 atoms of hydrogen and 1 atom of oxygen. O2 is the chemical formula for one molecule of
oxygen. A single molecule of oxygen has 2 atoms of oxygen.

You need to be able to tell which elements are in a chemical formula and how many atoms of each element are
in the formula.

A subscript is a small number written below and to the right of an element in a chemical formula. The subscript
tells how many atoms of the element there are in the formula.

A chemical equation is made of the chemical formulas of the reactants and products of a chemical reaction.

The reactants are on the left of the arrow, and the products are on the right of the arrow.

The reactants are the substances present before the reaction occurs.

The products are the substance present after the reaction occurs.

An arrow that points to the right separates the reactants from the products.

A chemical equation must be balanced. That means the atoms of the reactants must exactly match the atoms of
the products.

The law of conservation of mass states that matter cannot be created or destroyed; it merely changes form.
This is why the chemical equation must be balanced.

To balance an equation, a chemist can add coefficients to the left of the molecules to balance out the atoms.
The chemist must never change the subscripts to make the equation balance.

You must be able to recognize if an equation is balanced.

You must be able to add coefficients to balance an equation.

Chemical reactions all have one thing in common—they all produce a new substance.

Evidence of a chemical reaction:

o
color change
o
temperature change/and possibly light is given off
o
gas formation
o
formation of a precipitate
A chemical change is not the same as a physical change!! Physical changes include things like melting, freezing,
condensing, evaporating, changing shape, size, mass, or density. These all describe changes to physical
properties. DO NOT CONFUSE PHYSICAL AND CHEMICAL CHANGES!!

Exothermic reaction-releases thermal energy (gets hotter)

Endothermic reaction-absorbs thermal energy (gets cooler)

4 types of chemical reactions:
o
synthesis
o
decomposition
o
single replacement
o
double replacement

Be able to recognize each type of chemical reaction. Synthesis means put together. Decomposition means take
apart. Single replacement means one partner changes place. Double replacement means both partners change
place.