WHAT ARE ATOM AND ELEMENTS?

ATOMS AND ELEMENTS

AN ATOM IS THE SMALLEST UNIT OF AN ELEMENT THAT STILL HAS THE SAME PROPERTIES OF THAT ELEMENT.

AN ELEMENT IS THE SIMPLEST FORM OF MATTER BECAUSE IT CONTAINS ONLY ONE TYPE OF ATOM (CARBON, OXYGEN,HYDROGEN)

ATOMS

ATOMS CONTAIN SMALLER PARTICLES CALLED PROTONS, NEUTRONS, AND ELECTRONS.

PROTONS, NEUTRONS, AND ELECTRONS

ALL PROTONS ARE ALIKE.

ALL NEUTRONS ARE ALIKE.

ALL ELECTRONS ARE ALIKE.

THEY DO NOT HAVE THE PROPERTIES OF ANY OTHER ELEMENT.

THE PERIODIC TABLE

ELEMENTS ARE THE BUILDING BLOCKS OF ALL MATTER.

EVERYTHING IN THE WORLD IS MADE FROM COMBINATIONS OF ELEMENTS.

ATOMS OF EACH ELEMENT HAVE A CERTAIN NUMBER OF PROTONS.

THE NUMBER OF PROTONS IN AN ATOM IS ITS ATOMIC NUMBER.

PERIODIC MEANS REPEATING PATTERN

THE PERIODIC TABLE IS A CHART WHERE ELEMENTS ARE ARRANGED IN ORDER OF ATOMIC NUMBERS.

ATOMIC NUMBERS INCREASE AS YOU MOVE ACROSS A ROWW AND DOWN A COLUMN.

ALL THE ELEMENTS ON THE LEFT SIDE OF THE TABLE, EXCEPT HYDROGEN, ARE METALS.

THE ELEMENTS ON TH EFAR RIGHT ARE NONMETALS AND MANY ARE GASES.

ONLY TWO ELEMENTS ARE LIQUIDS AT ROOM TEMPERATURE, MERCURY AND BROMINE.

THE ELEMENTS IN EACH COLUMN HAVE SIMILAR PROPERTIES.

MOLECULES AND COMPOUNDS

ELEMENTS ARE RARELY FOUND IN THEIR PURE FORMS IN NATURE.

A COMPOUND IS A SUBSTANCE MADE OF ATOMS FROM TWO OR MORE ELEMENTS THAT HAVE COMBINED CHEMICALLY.

A COMPOUND HAS A FORMULA-SYMBOLS THAT SHOW HOW MANY ATOMS OF EACH ELEMENT ARE PRESENT.

PURE SUBSTANCES INCLUDE ELEMENTS AND COMPUNDS.

IN A PURE SUBSTANCE, ALL PARTICLES ARE ALIKE.

THE SMALLEST UNIT OF A COUMPOUND THAT CAN EXIST IN NATURE IS A MOLECULE.

TWO ATOMS OF THE SAME ELEMENT BOND TO FORM A MOLECULE.

PHYSICAL PROPERTIES

PHYSICAL PROPERTIES ARE THE TRAITS THAT DESCRIBE A SUBSTANCE BY ITSELF, NOT BY THE WAY IT COMBINES WITH OTHER SUBSTANCES.

EXAMPLES OF PHYSICAL PROPERTIES:

SMELLTASTETEMPERATUREMASS

PHYSICAL CHANGE IS WHEN A SUBSTANCE CHANGES BUT THE STAYS THE SAME SUBSTANCE.

EXAMPLE: WATER IS STILL WATER NO MATTER WHAT STATE IT IS IN. IT CHANGES ITS PROPERTIES, BUT IT IS STILL WATER.

SOLUBILITY IS THE ABILITY TO DISSOLVE.

THIS IS ALSO A PHYSICAL PROPERTY.

EXAMPLE: SUGAR CAN DISSOLVE IN WATER.

WHEN THE SUGAR DISSOLVES, THE SUGAR MOLECULES ARE STILL THERE, THEY ARE JUST SO SMALL YOU CAN’T SEE THEM.

OIL WATER WILL NOT MIX. THE WORDS DISSOLVE AND

MIX ARE CLUES THAT A PHYSICAL CHANGE HAS HAPPENED.

A MIXTURE IS A COMBINATION OF TWO OR MORE SUBSTANCES IN WHICH THE SUBTANCES THEMSELVES ARE NOT CHANGED.

THE SUBSTANCES UNDERGO A PHYSICAL CHANGE WHEN THEY ARE MIXED, BUT CAN BE SEPARATED FROM THE MIXTURE.

A MIXTURE IN WHICH ALL PARTS ARE MIXED EVENLY IS CALLED A SOULTION.

METALS

A METAL IS A SUBSTANCE THAT IS A GOOD CONDUCTOR OF HEAT AND ELECTRICITY.

ABOUT 75% OF ALL ELEMENTS ARE METALS.

METALS ARE MALLEABLE-EASY TO SHAPE, BEND, AND FORM.

METALS ARE ALSO DUCTILE, WHICH MEANS THEY CAN BE PULLED INTO THIN STRANDS WITH BREAKING.

NONMETALS

NONMETALS ARE SUBSTANCES THAT DO NOT HAVE THE PROPERTIES OF METAL.

PROPERTIES OF METALS

ALL THE ELEMENTS N THE SAME COLUMN OF THE PERIODIC TABLE ARE CALLED A FAMILY, SO THESE ELEMENTS ARE RELATED.

MOST METALS IN A FAMILY HAVE THE SAME PHYSICAL PROPERTIES.

SOMEPROPERTIES OF METALS INCLUDE: MELTING POINT BOILING POINT HOW THEY REACT WITH

OTHER SUBSTANCES

ALLOY

An alloy is a solid solution made by combining metals or a metal and a nonmetal.

An alloy has properties that are different from the elements that the alloy contains.

Examples of alloy: Steel Brass Pewter Stainless steel

METALLOIDS

METALLOIDS ARE ELEMENTS THAT HAVE SOME PROPERTIES OF METALS AND SOME PROPERTIES OF NONMETALS.

METALLOIDS ARE ALSO CALLED SEMIMETALS.

CHEMICAL PROPERTIES

A CHEMICAL PROPERTY IS THE WAY A SUBSTANCE REACTS, OR COMBINES, WITH OTHER SUBSTANCES TO FORM NEW SUBSTANCES.

CHEMICAL REACTIONS

A CHEMICAL REACTION IS A CHEMICAL CHANGE THAT RESULTS IN ONE OR MORE NEW SUBSTANCES.

Mixing the ingredients together to make a cake is a physical change because you can separate the ingredients again. Baking the cake is a chemical change because a new substance forms.

Reactants and Products

Every chemical reaction begins with one or more reactants.

A reactant is one of the starting materials in a chemical reaction.

A product is one of the ending materials of a chemical reaction.

Salt

If you start with the reactants-sodium and chloride you end up with the product-table salt.

When sodium and chloride combine the form a new substance-salt.

Iron Oxide

When iron and oxygen combine, they form a new product-iron oxide or rust.

Salts

A salt is the product that occurs when an acid and a base react.

Most salts have similar physical and chemical properties.

Salts: are hard, but brittle (break

easily) Dissolve easily in water Salt solutions have high

electrical conductivity Change the freezing point of

water Used preserve food