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Combinations of Atoms
Chapter 4.2
Page 87
Organization of the Periodic Table
Each Box gives information about one element
Name of element
Atomic number (number of
protons)
Atomic Symbol
Atomic Mass
Now for the Periodic Table as a Whole
Position on table shows electron arrangement
Periods—________________________ rows
Give number of electron ___________________ used
Groups—____________________ columns
Within a column elements have the same number of _____________ electrons
Molecules
Atoms are the building blocks of _____________________
The smallest unit of matter that can exist by itself and retain all
of a substances chemical properties
In a molecule two or more atoms are bonded together
Diatomic molecules di--two
Some molecules are made of the __________ kind of atom
What kind of molecule is O2? _____________________
Ozone is ____________________
Chemical Formulas
A combination of letters and numbers that
shows ________________ of atoms of
each element that are required to make a
______________ of the compound
Chemical Equations
Elements and compounds often combine through chemical _________________
The reaction can be described in a ________________
Photosynthesis formula
6H2O + 6CO2 -------> C6H12O6+ 6O2
Coefficient
Subscript
___________________on left
_______________ on right
The arrow is read ________________
Balanced equations
An equation is _____________ when the number of atoms on the right
______________ the number of atoms of the __________ element on the left
To balance a formula you use ______________________
How to balance an equation
Book example
Magnesium, Mg, reacts with oxygen, O2, to form MgO, magnesium oxide
Mg + O2
MgO
We have two oxygen on the left so we will need a number 2 on the right as a
coefficient
Mg + O2
2MgO
No we have two oxygen on each side but we only have one magnesium on the left, so we
will need a coefficient in front of the Mg.
2 Mg + O2
2MgO
Now this is balanced!
Chemical Bonds
The forces that hold together the atoms in molecules are called
_______________________ _______________________
Bonds form because of attraction between __________________ charges
Atoms can share or transfer __________________ electrons
Ions
When an electron is ________________from one atom to another both
atoms become ____________________
A charged particle like an atom or molecule is an
_______________________
A positively charged ion is a ______________.
A negatively charged ion is an ____________________.
Ionic Bonds
Attractive force between two ____________charged ions that result from the
___________ of electrons from one atom to another is called an ________ bond.
Na from the left of the periodic table wants to _____________ _____________
It becomes a ___________________
Cl from the right side of the periodic table wants to _______________ electrons
It becomes an ________________________.
Ionic bonds form from atoms from _______________ sides of the periodic table
Covalent Bonds
A bond between atoms that ________ electrons is called a __________
bond
Polar Covalent Bonds
Some atoms that are covalently bonded do not equally share
elections
A covalent bond with unequal attraction is called a ________
_____________ bond
________________is one example
Metallic Bonds
Electrons ____________ easily
They are not _____________bound
This explains the properties of ______________________
Ben Franklin found electricity was a flow of ________________________
Physical Change
A change of matter from one form to another without a change in ________
formula (properties)
___________________
___________________
_____________________
______________________ of State is a physical change
An item can change from solid to liquid to gas and still have the same chemical
_______________________________
_______________________is a physical change
Example: dissolve salt in water
You still have salt and water. You could evaporate the water and get the salt back
Something that dissolves is ________________________________
Chemical Changes
Cannot be reversed by ________________ means
Form ______________substances with different
________________ properties
Can be detected by:
Fizz
Smell
Color change
Produce heat ________________reaction
Produce cold ________________ reaction
Produce sound
Mixtures
A combination of two or more substances that are not _____________ combined
Two types:
Heterogeneous--______________
Homogenous--_________________
Solution
A homogenous mixture of two or more substances that are uniformly dispersed
When a substance _________ it goes into ________________________
Example-- salt in water Something that dissolves is _____________________.
Compounds can be broken down by physical means
_______________________ acid in pop gives it fizz
When the bottle is opened the acid breaks down into ______________ and
water
Carbon dioxide escapes as _______________________
Mixtures can be physically ________________________________
By
___________________________
___________________________
___________________________
Mental Lab Activity
Design an experiment to separate the mixture in a sample that contains
Sand Poppy seed Salt Iron filings
—list the steps you will take below
Test for the presence of CO2 and H2
A flaming _______ is used to detect the presence of carbon dioxide or hydrogen gas
CO2 ______________s the flame
H2 Creates a hydrogen ______________ or bark