Chemical Interactions

Investigation #1 Elements

Part 1 The Periodic Table Big Idea #1 An element is a basic substance that cannot be broken into simpler substances during chemical interactions.

Big Idea #2 There are 90 naturally occurring elements on Earth.

Big Idea #3 Elements combine to make all the substances on Earth.

Big Idea #4 The periodic table of the elements is a chart that displays all of the naturally occurring and synthesized (man made) elements.

Big Idea #5 The abundance of elements varies with location in the universe. --- not the same amount everywhere you go.

THE ATOM

ATOMIC ANATOMY The simplest atom is made up of the following parts: an electron cloud -- a nucleus – a proton – a neutron -- an electron

Protons Protons are located in the nucleus. Protons have a positive charge. Protons give an element its identity. The number of protons will not change. The number of protons is equal to the atomic number.

Neutrons Neutrons are located in the nucleus. Neutrons have a neutral (no) charge. The number of neutrons in any element may change, this is called an ISOTOPE. Neutrons have the same mass as a proton.

Electrons Electrons are located in the electron cloud. Electrons have a negative charge. Electrons are very energetic (they move a lot) Electrons have almost zero measurable mass.

Other notes… The total number of protons equals the atomic number of an element. The total number of protons plus the total number of neutrons equals the atomic mass number of an element think about this carefully ?????

Metals Metals are good conductors of heat and electricity. Metals are shiny with high melting points. Metals are ductile; they can be pulled into thin wires. Metals are malleable; they can be hammered into thin sheets.

Nonmetals Poor conductors of heat and electricity. Usually have dull surfaces and low melting points. The solids are brittle; they break easily. Some gases, oxygen for example, are also considered nonmetals.

Metalloids Some elements do not fit easily into the metal or nonmetal category. Weird? Where do they belong? --- Metalloids have some metallic properties and some nonmetallic properties. (may conduct heat but not that well)

Halogens Strongly nonmetallic elements. The most active nonmetals. Combine with metals to form salt compounds. ---Example…..Chlorine gas (Halogen) combines with Sodium (metal) to form common table salt.

Noble Gasses All 6 members of this group are colorless gasses. These gases are the most nonreactive elements. All 6 are found in the atmosphere of Earth.

Rare Earth Elements Lanthanoid Series – very shiny soft malleable metals very conductive Actinoid Series – radioactive (unstable) synthetic (made in lab)

Investigation #2 Substances

Part 1 Mystery Mixture Big Idea #1 A substance is a form of matter with a unique composition and distinct properties.

Big Idea #2 A mixture is made when two or more substances physically (not chemically) combine. - salad - saltwater - Gatorade - peas and carrots

Part 2 Mixing Substances Big Idea # 1 Chemical names communicate information about the composition of substances.

Big Idea #2 Chemical formulas communicate the composition of substances.

Big Idea #3 A chemical reaction occurs when substances interact to form new substances (products).

Big Idea #4 A chemical reaction provides evidence that starting substances change into new, different substances.

Notes A substance is a form of matter. There are millions of different substances on Earth. Each substance is different from every other substance.

Mystery Mixture Analysis Which combinations of two substances resulted in fizzing? List all. Which two substances do you think make up the mystery mixture? What evidence do you have to support your conclusion?

Chemical Reaction The process by which one or more substances may be transformed into one or more new substances.

Signals of a Chemical Reaction Production of a gas. (bubbling/fizzing) Formation of a solid. (precipitate) Change in color. Production of heat and/or light.