Unit 3: Atoms and Elements – Review Notes
name:_______________________
period: ______________
Main Idea
Supporting Details/Answer
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What is an atom?
The smallest particle into which an element can be divided and still be the same substance.
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What is an element?
Pure substance that can’t be separated into simpler substances by physical or chemical changes.
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Draw and identify the basic parts of a periodic table.
7
N
Nitrogen
14 amu
Atomic #
Symbol
Name
Atomic Mass
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Where are protons, neutrons and electrons located in an atom?
Protons = nucleus
Neutrons =nucleus
Electrons = electron cloud
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What is an atom mostly made up of?
empty space
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What are the charges on a proton, neutron and electron?
Protons = positive
Neutrons =no charge; neutral
Electrons = negative
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Where is most of the mass of an atom located?
Nucleus because protons and neutrons are in the nucleus and they both have mass
Electrons are in the electron cloud and have almost no mass
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What units are used to measure the mass of an atom?
amu= atomic mass unit
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Describe how to determine the number of protons in a specific atom using the periodic table.
The atomic number = number of protons
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Describe how to determine the number of electrons in a specific atom using the periodic table.
Electrons = protons in neutral atoms
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Describe how to determine the number of neutrons in a specific atom using the periodic table.
Neutrons = atomic mass - protons
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What are some of the patterns on the periodic table?
Down a group: atomic radius increases, number of energy level increases, reactivity is same, number of valence electrons is same
Across a period: number of valence electrons increases, number of energy levels is same
Group # = number of valence electrons
Period # = number of energy levels
Metals are on the left
Nonmetals are on the right
Metalloids are along the zig zag line that separates metals and nonmetals
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What determines the type of element?
The atomic number = number of protons.
The number of protons an atom has = the type of element. No two different elements have the same number of protons.
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What is all matter made of?
Atoms.
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What are the periods and groups on the periodic table?
Properties of matter are ways of describing matter.
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Define chemical property of matter:
A chemical property of matter can only be observed by reacting matter with other matter to create a new type of matter. Chemical properties describe the ability of a type of matter to react with other matter.
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Define physical property of matter:
A physical property can be observed without changing the matter into a new substance.
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Practice drawing Bohr models. Tell how many electrons the first three energy levels can hold.
1st energy level holds 2 electrons
2nd energy level holds 8 electrons
3rd energy level holds up to 18 but is considered full with 8 electrons
6
C
Carbon
12.0
Atomic number
1. Identify
Element symbol
Element name
Atomic mass
Word
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Definition
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Atomic Number
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The number of protons in an atom. In a neutral atom it is also the number of electrons.
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Chemical Symbol
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The symbol that represents that element
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Element Name
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The name of the element
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Mass Number
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The mass of an atom of that element. It is the total number of protons and neutrons.
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10
10
3
3
neon
10
20.18
10
4
3
6.941
lithium
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