Download Atoms Review

Atoms Review
Size of Atoms
• Remember our zoom in on Atoms?
• How small are atoms?
• What are Atoms?
Elements
What is the definition of an element?
What are some examples of elements?
Scientific Shorthand
Element
Symbol
Aluminun
Al
Iron
Fe
Gold
Au
Mercury
Hg
Oxygen
O
Chlorine
Cl
Why the weird Short hand?
• Silver is argentum in Latin - hence Ag
• Gold is aurum in Latin - hence Au
• Potassium is named after the Latin word for “alkali” kalium - hence K.
Potassium is one of the alkali metals
• Mercury’s former name was “hydrargyrum” from the Greek words
for water and silver – Hg
• Sodium from the Latin natrium - hence Na
• Iron from the Latin ferrum - hence Fe
Why use Chemical Symbols?
• ● Easier to write
H v. Hydrogen, or H2O for dihydrogen oxide
• ● Used worldwide
Scientists regardless of language use chemical symbols
Parts of Atoms
• Where is the nucleus and Electron Cloud?
• Which particles are protons? Electrons? Neutrons?
What Makes up an Atom?
• Nucleus - small positively charged center of an atom.
• Protons - particles with a charge of 1+
• Neutrons - particles with no electrical charge
• Electrons - particles with a charge of 1• Atoms of different elements differ in the number of protons they
contain
Reading the Periodic Table
• If the atomic number is 7, how protons are there? How many
electrons?
• If the atomic mass is 14.95, how many neutrons are there?
Using the Period table Practice
• Turn to the periodic table in your planner (R-13), and find out how many
protons, neutrons, and elections are in each of these elements.
• Na
•S
• Ar
• Ti
• Be
• In
•N
• Br
molecules
What is the definition of a Molecule?
What are some examples?
All Compounds are molecules!!
What is the definition of a
compound? Examples?
Why Do we have different States of Matter?
• What are the states of matter like?
STATES OF MATTER
SOLID
Tightly packed, in
a regular pattern
Vibrate, but do not
move from place
to place
LIQUID
Close together
with no regular
arrangement.
Vibrate, move
about, and slide
past each other
GAS
Well separated
with no regular
arrangement.
Vibrate and move
freely at high
speeds
PLASMA
Has no definite
volume or shape
and is composed
of electrical
charged particles
History of atoms
• What are some discoveries scientists have made about atoms since
Democritus?
Quantum Mechanical Model
Composition of Matter Notes
1 Pure Substances
• Materials are made of a pure substance or a
mixture of substances.
• A pure substance, or simply a substance, is a
type of matter with a fixed composition.
• A substance can be either an element or a
compound.
Composition of Matter
1
Elements
• All substances are built from atoms. If all the
atoms in a substance have the same identity,
that substance is an element.
• The graphite in your
pencil point and the
copper coating of
most pennies are
examples of
elements.
Composition of Matter
1
Compounds
• Can you imagine yourself putting something
made from a slivery metal and a greenishyellow, poisonous gas on your food?
Composition of Matter
1
Compounds
• Table salt is a chemical
compound that fits this
description. Even though
it looks like white crystals
and adds flavor to food,
its components—sodium
and chlorine—are neither
white nor salty.
Composition of Matter
1
Mixtures
• A mixture, such as
the pizza or soft drink
shown, is a material
made up of two or
more substances that
can be easily
separated by physical
means.
Composition of Matter
1
Heterogeneous Mixtures
• Unlike compounds, mixtures do not always
contain the same proportions of the
substances that make them up.
• A mixture in which different materials can
be distinguished easily is called a
heterogeneous mixture.
Composition of Matter
1
Heterogeneous Mixtures
• Most of the substances you come in contact
with every day are heterogeneous mixtures.
Some components are easy to see, like the
ingredients in pizza, but others are not.
• For example, the cheese in
pizza is also a mixture, but
you cannot see the
individual components.
Composition of Matter
1 Homogeneous Mixtures
• Soft drinks contain water, sugar, flavoring,
coloring, and carbon dioxide gas.
• Soft drinks in sealed
bottles are examples
of homogeneous
mixtures.
Composition of Matter
1
Homogeneous Mixtures
• Another name for homogeneous mixtures
like a cold soft drink is solution.
• A solution is a homogeneous mixture of
particles so small that they cannot be seen
with a microscope and will never settle to
the bottom of their container.
• Solutions remain constantly and uniformly
mixed
Breakdown of Matter
Matter
Pure
Substances
Element
Mixtures
Compound
Heterogeneous
Mixture
Homogeneous
Mixture
Quick Practice
Substance
Soda
Steel
Oxygen
Iron filings
smoke
Limestone (CaCO3)
Mixture or Pure
Homogeneous or
Heterogeneous
Key Concepts
Every sample of a given substance has the same properties because a substance has a fixed, uniform composition
An element has a fixed composition because it contains only one type of atom
A compound always contains two or more elements joined in a fixed proportion
The properties of a mixture can vary because the composition of a mixture is not fixed