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Elements and the Periodic Table
Classification arranging items into
groups or categories according to some criteria.
act of classifying creates a pattern helps you recognize
and understand the behavior of fish, chemicals, or any matter in your surroundings.
Classifying Matter
Matter is usually defined as anything that has mass and occupies space.
Gas Liquid Solid
Total disorderLots of empty space
DisorderSome spaceParticles closertogether
OrderParticles fixed in position
Solids
Liquids
Gases
have a definite volume and shape
definite volume, indefinite shape, takes on the shape of the container
have no defined shape or volume, will spread until evenly distributed
Mixtures and Pure Substances
Mixture a combination of two or more substances in which each substance keeps at least some of its original properties.
Heterogeneous mixture .
Homogeneous mixture
Pure substances
has physically distinct parts with different properties, can be recognized by sight.
is the same throughout the sample, cannot identify by sight.
are substances with a fixed composition
Elements
a pure substance which cannot be broken down into anything simpler by either physical or chemical means.
simplest form of matter that can exist under normal laboratory conditions.
Elements Science has come
along way since Aristotle’s theory of Air, Water, Fire, and Earth.
Scientists have identified 90 naturally occurring elements, and created about 28 others.
Elements The elements, alone
or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe.
The most abundant element in the earth’s crust is oxygen.
Compound
a pure substance that can be decomposed by a chemical change into simpler substances with a fixed mass ratio.
Sugar (A) is a compound that can be easily decomposed to simpler substances by heating. (B) One of the simpler substances is the black element carbon, which cannot be further decomposed by chemical or physical means.
The Periodic Table and the ElementsThe Periodic Table and the Elements
What is the periodic table ?What is the periodic table ? What information is obtained from the table ?What information is obtained from the table ?
SymbolAtomic Mass
Atomic Number
Charge (if ion)
HHydrogenHydrogen
1
1
Protons: 1Neutrons: 0Electrons: 1
NaSodiumSodium
23
11
Protons: 11Neutrons: 12Electrons: 11
Dmitri Mendeleev (1869)In 1869 Mendeleev and Lothar Meyer In 1869 Mendeleev and Lothar Meyer (Germany) published nearly identical (Germany) published nearly identical classification schemes for elements known classification schemes for elements known to date. The periodic table is base on the to date. The periodic table is base on the similarity of properties and reactivities similarity of properties and reactivities exhibited by certain elements. Later, Henri exhibited by certain elements. Later, Henri Moseley ( England,1887-1915) established Moseley ( England,1887-1915) established that each elements has a unique atomic that each elements has a unique atomic number, which is how the current periodic number, which is how the current periodic table is organized.table is organized.
http://www.chem.msu.su/eng/misc/mendeleev/welcome.html
Mrs. LaRosa
Some images are from www.chem4kids.com
www.middleschoolscience.com 2008
Metal
Non-Metal
Elements that are usually solids at room temperature. Most elements are metals
Elements in the upper right corner of the periodic table. Their chemical and physical properties are different from metals.
Metalloid Elements that lie on a diagonal line between the metals and non-metals. Their chemical and physical properties are intermediate between the two.
Properties of Metals Metals are good
conductors of heat and electricity.
Metals are shiny. Metals are ductile (can be
stretched into thin wires). Metals are malleable (can
be pounded into thin sheets).
A chemical property of metal is its reaction with water which results in corrosion.
Properties of Non-Metals Non-metals are poor
conductors of heat and electricity.
Non-metals are not ductile or malleable.
Solid non-metals are brittle and break easily.
They are dull. Many non-metals are
gases.
Sulfur
Properties of Metalloids Metalloids (metal-like) have
properties of both metals and non-metals.
They are solids that can be shiny or dull.
They conduct heat and electricity better than non-metals but not as well as metals.
They are ductile and malleable.
Silicon
Families on the Periodic TableElements on the periodic table can be
grouped into families bases on their chemical properties.
Each family has a specific name to differentiate it from the other families in the periodic table.
Elements in each family
react differently with
other elements.
The periodic table is made up of rows of elements and columns.An element is identified by its chemical symbol.The number above the symbol is the atomic numberThe number below the symbol is the rounded
atomic weight of the element.A row is called a periodA column is called a group
Key to the Periodic Table Elements are organized on the
table according to their atomic number, usually found near the top of the square. The atomic number refers to
how many protons an atom of that element has.
For instance, hydrogen has 1 proton, so it’s atomic number is 1.
The atomic number is unique to that element. No two elements have the same atomic number.
What’s in a square? Different periodic
tables can include various bits of information, but usually: atomic number symbol atomic mass number of valence
electrons state of matter at room
temperature.
Common Elements and Symbols