CHEMISTRY

BIG IDEAS

•The number of protons in the nucleus of an atom determines what the element is.

•The way that electrons are organized around the nucleus of an atom determines how it interacts with other substances.

•Atoms join together chemically to create strong bonds resulting in new substances called compounds.

Atomic Structure

Main Ideas:An atom is the smallest part of an element that can exist and still be identifiable as that element; building blocks of elements.

An element a type of matter made of many identical atoms.

An atom is the smallest part of an element that can exist.

An element is a substance made up of a single type of tiny particles called atoms.

Meet the Elements Song- TMBG

Elements Song- Tom Lehrer

What are atoms?

-Atoms are the basic building blocks of matter that make up everyday objects. -A desk, the air, even you are made up of atoms!-There are 90 naturally occurring kinds of atoms.

How do atoms get their identity?

# of PROTONS

= atomic number

ATOMIC NUMBER and MASS NUMBER

Atomic numberAtomic number

1212

66C

Mass numberMass number

Number of protons (+)

Protons + Neutrons

Elemental Notation• Atomic

Number – the number of protons in the nucleus of the atom.

• Atomic Mass – the total number of protons and neutrons in a nucleus.

Molecules are a single unit of 2+ atoms bonded together.

usually same type of atom

Compounds are many molecules; made of 2+ different elements (different

types of atoms) that are chemically bonded together so elements have new properties (ex: NaCl)examples of differences between molecules and compounds

Magnesium Atoms

Oxygen Atoms

Molecules of magnesium oxide

Summary

element element compound

atom atom molecule

Compounds are pure substances made of 2 or more elements chemically BONDED together.

Which are molecules and which are compounds?

Li+ + H2O LiOH + H2

If lithium is added to water, lithium reacts with the water molecule forming lithium hydroxide and hydrogen gas.

Alkali

Vinegar Chemical Formula: C2H4O2

vanilla Chemical Formula: C8H8O3

Vitamin C Chemical Formula: C6H8O6

water Chemical Formula: H2O ozone Chemical Formula: O3

Salt Chemical Formula NaCl

carbon dioxide Chemical Formula: CO2

carbonic acid ( taste in soda) Chemical Formula: H2CO3

citric acid oranges and lemons Chemical Formula: C6H8O7

dynamite Chemical Formula: C7H5N3O6

alcohol Chemical Formula: C2H6O sugar Chemical Formula: C12H22O11

bleach Chemical Formula: H2O2

methane Chemical Formula: CH4

nutrasweet Chemical Formula: C14H18N2O5

Count the atoms for each element that makes up the following compounds:

Example:

Water – H2O

2 atoms of Hydrogen

1 atom of oxygen

COUNTING ATOMS

A MIXTURE is a material made up of 2+ substances which may be elements or compounds that are NOT CHEMICALLY BONDED.

Properties of Mixtures

• The composition of a mixture is variable.

• Each of its components retains its characteristic properties.

• Its components are easily separated.

Which are mixtures and which are compounds?

• soil

• ocean water (H20 + NaCl)

• air (O2 + N2 + CO2 + Ar)

• water (H2O)

• table salt (NaCl)

• Sugar (C12H22O12)

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mixtures.html

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Atom Molecule

Mixture Compound

Element