Elements and Compounds

Page 12 in Journal

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Atom

Smallest thing you can break matter down into while still keeping its original identity.

Atoms are used to create the elements.

Elements are used to create everything in the world.. .

So far, there are over 100 known elements.So far, there are over 100 known elements.

An element is a substance in which all of its atoms are the

same. 

Element

Gold is an Gold is an element.element.An element is a substance which An element is a substance which cannot be broken down into simpler cannot be broken down into simpler substances under normal substances under normal circumstances.circumstances. This means that if you This means that if you break gold down into break gold down into smaller and smaller smaller and smaller pieces, it will still be pieces, it will still be gold.gold.

Gold is made of nothing Gold is made of nothing

. . . but gold.. . . but gold.

Gold cannot be Gold cannot be broken down into any broken down into any other substances.other substances.

The smallest, tiniest The smallest, tiniest piece of goldpiece of gold

is an atom of goldis an atom of gold..

An atom is the smallest unit of an element.An atom is the smallest unit of an element.

Oxygen (65%)

Carbon (18%)

Hydrogen (10%) THE HUMAN BODY Nitrogen (3%)

Calcium (1.5%)

Phosphorus (1.0%)

Potassium (0.35%)

Sulfur (0.25%)

Sodium (0.15%)

Magnesium (0.05%)

Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine,

Manganese, Cobalt, Iron (0.70%) Lithium, Strontium, Aluminum,

Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

Where do we find the list of all the elements?

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The Periodic Table

• Dimitri Mendeleev was the Russian scientist who developed the modern Periodic Table

• The Periodic Table is an arrangement of all elements in

order of atomic number.

What is the symbol for beryllium?

Be

What do you notice about the first and last letters of thesymbol?

The first letter is always a capitaland the following letters are always small letters.

What is the name of this element?

Tells how many protons are in the atom

Tells the mass of the atom of lithium

Is the symbol for lithium.How do I know it is only one element and not two put together?

Element – a pure substance. It can NOT decompose into another

substance.

Decompose – break down

Stop here and finish the Periodic Table

Salt is Salt is notnot an an element.element.

Salt can be broken Salt can be broken down into simpler down into simpler substances--sodium substances--sodium and chlorine.and chlorine.

Salt is Salt is notnot an an element.element.Salt can be broken Salt can be broken down into simpler down into simpler substances--sodium substances--sodium and chlorine.and chlorine.

Salt is made up of more than 1 element. Salt is made up of more than 1 element.

We call that a compound.We call that a compound.

A A compoundcompound is matter that is made up of more is matter that is made up of more

than 1 kind of element.than 1 kind of element.

Salt is made up of 2 elements. So salt is a _______________.

Salt is made up of sodium, which has the symbol _______ and chloride which has the symbol __________.

We can represent salt with the formula_________.

compound

NaCl

NaCl

In a compound, the different elements are chemically bonded together.

A formula tells us what elements are in matter and how many atoms there are of the element.

K3CrO2

3 atoms ofpotassium

1 atomof chromium

2 atoms ofoxygen

These atoms are bonded together chemically!

Write down these formulas. Tell what elements they are made up of and how many atoms there are in each substance.

H2O2

HCl

NaH2CO3

2 atoms hydrogen, 2 atoms oxygen

1 atom hydrogen, 1 atom chloride

1 atom sodium, 2 atoms hydrogen 1 atom carbon, 3 atoms oxygen

Why are these compounds?More than 1 type ofelement is bound together.

Why do you think the second letter is not a capital?

NACLO NaClO

How manyelements areshown?

Cannot tell SodiumChlorideOxygen

Meet the elements

Identify the compounds.

O2 NaCl H

CO2 Li2

On your next clean page, draw the pictures below. Label each of the boxes. The circles represent atoms of an element.

Element Mixture Compound