Download Nucleus Protons Neutrons Electron Cloud Electrons

Name: ___________________________
Date:_____________________________
Pd:______
Unit 2: Atomic Structure: Isotopes Guided Notes
Atoms: The Building Blocks of everything?
An atom is the smallest unit of an element that is possible.
 All the matter around us is made of individual atoms. Sometimes different atoms join
together to form new substances.
o Two Hydrogen Atoms will join an Oxygen atom and form water (H2O).
 In this sense atoms are the building blocks of matter but atoms are usually made up of three
smaller particles and two of those particles are made up of even smaller particles.
o So an atom is not a _________________________________ building block of matter.
An atom consists of a
Nucleus (protons and neutrons)
•
Electrons in space about the nucleus.
Nucleus
•
Protons
Electron
Cloud
Neutrons
Electrons
•
Positively charged (+1).
•
Found in the nucleus.
•
_____________________________________________________
•
Neutral particle in an atom.
•
Found in the nucleus.
•
______________________________________________________
•
Negatively charged particle (-1).
•
Found outside the nucleus.
•
_______________________________________________________

The atom is mostly empty space
o Most of the mass of an atom is in the ____________________________________
•
Protons and Neutrons are roughly equal in mass but a neutron is ever so
_____________________ bigger than a proton.
•
Therefore we say the each has a mass of __________ amu (atomic mass unit)
•
A proton (and a neutron) are about 1800 times as massive as an electron.
Proton
Neutron
Electron
Proton
Electrons

Travel around the nucleus in the electron cloud which is mostly empty space

In a ___________________ atom the number of electrons is _________________ the number of protons since
that is the only way to have a “net” charge of ____________________.
Essential Question: How can nuclei of the same element differ?
Name: ___________________________
Date:_____________________________
Pd:_____
PART I: ATOM SCREEN
Go to the website: phet.colorado.edu. Click on HTML5 simulations on top right of screen and choose the Build an Atom simulation
(http://phet.colorado.edu/en/simulation/build-an-atom)
Click on the Atom
icon
Explore Protons:
1. Click the green signs
to show Element.
2. Drag one proton and one electron to the atom. Record the Element:__________________
3. Drag an additional proton to the model. Record the Element:________________________
4. Drag an additional proton to the model. Record the Element:______________________
5. What happened when additional protons were placed in the atom?
________________________________________________________________________________
Explore Neutrons:
1. Click
to reset the simulation
2. Click on
at the bottom of the screen
3. Click the green +
sign to show Symbol
4. Drag three protons, three neutrons, and three electrons to the model. Record the Symbol: ________.
5. Drag an additional neutron to the model. Record the Symbol: ____________.
6. Drag an additional neutron to the model. Record the Symbol: ____________.
7. What happened when additional neutrons were placed in the atom?
________________________________________________________________________________
Explore Electrons:
1. Click
to reset the simulation
2. Click on
3. Click the green +
at the bottom of the screen
sign to show Symbol
3. Drag four protons, five neutrons, and three electrons to the model. Record the Symbol: ________.
4. Drag an additional electron to the model. Record the Symbol: ____________.
5. Drag an additional electron to the model. Record the Symbol: ____________.
6. What happened when additional electrons were placed in the atom?
Activity Questions
1.
What particle determines what element you have? _______________________________________
Essential Question: How can nuclei of the same element differ?
Name: ___________________________
2.
Date:_____________________________
Pd:_____
What particle(s) can change without changing the identity of an element? ____________________________
Key Vocabulary
Isotope – atoms of the same element that have the same number of _______________but a different number of
_________________________
Ions – atoms of the same element that have the same number of __________________
but different number of _________________________
•
All elements consist of naturally occurring isotopes and artificially produced isotopes
The isotopes of an element have:
•
_______________________Chemical Properties (this is because they have the same numbers of protons and
electrons and subatomic particles are responsible for chemical behavior)
•
___________________________Physical Properties (different mass and different number of neutrons)
Use the isotope symbol to determine the number of subatomic particles present in AN ATOM of the isotope
Use the periodic table to determine the number of subatomic particles present in an atom of the MOST
NATURALLY ABUNDANT isotope for that element
There are three types of hydrogen but the vast
majority of hydrogen is protium.
The atomic mass is a weighted average of all
the types of hydrogen.
So if you had a bag filled with hydrogen gas,
it would have all three types but most of it
would be protium.
Therefore, we _____________ the average
atomic mass to the nearest whole number.
Essential Question: How can nuclei of the same element differ?
Name: ___________________________
Date:_____________________________
Pd:_____
How to Read a Periodic Table Tile
11
2
8
1
Na
Sodium
22.9897
PART II: ISOTOPES
A NEUTRAL CARBON ATOM HAS HOW
MANY OF EACH
PARTICLE?
The 6 on the top is the atomic number of carbon and that is also
the number of protons any atom of carbon must have.
Protons: ____________
The 12.01 on the bottom is the average atomic mass and is also
the number of protons and neutrons in average carbon atom. Six
of those 12 must be protons because Carbon has an atomic
number of 6 so what is left over are neutrons.
Neutrons: __________
Electrons: __________
An electrically neutral atom must have an overall charge of 0.
This means the total number of electrons (-1 charge) must be
equal to the number of protons (+1 charge).
Essential Question: How can nuclei of the same element differ?
Name: ___________________________


Date:_____________________________
Pd:_____
Proton Number = Atomic Number.
Neutron Number: Atomic Mass (___________________) minus Atomic Number.
(or bottom minus top)

Electron Number = Proton Number (if Neutral)
Protons: _______
Neutrons: ______
Electrons: _____
Protons: _______
Neutrons: ______
Electrons: _____
Concept Check!
Why do we only consider the number of neutrons and protons when determining the mass number of an
atom?_____________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Essential Question: How can nuclei of the same element differ?
Name: ___________________________
Date:_____________________________
Essential Question: How can nuclei of the same element differ?
Pd:_____
Name: ___________________________
Date:_____________________________
Pd:_____
Isotope Classwork
Practice 1 – Use your Periodic Table to help you complete the following tables
Element
Element
Atomic
Name
Symbol
Number
Element
Element
Atomic
Name
Symbol
Number
Atomic Mass
# of Electrons
# of Protons
# of Neutrons
Atomic Mass
# of Electrons
# of Protons
# of Neutrons
Hydrogen
Oxygen
Sulfur
Gold
Lead
He
6
11
35.45
61
Practice 2
Element/Isotope
Element
Atomic
Atomic Mass/
Name
Symbol
Number
Mass Number
Fluorine
Argon -39
Neon-20
Neon-21
Essential Question: How can nuclei of the same element differ?
# of Electrons
# of Protons
# of Neutrons
Name: ___________________________
Date:_____________________________
Pd:_____
Neon-22
Element/Isotope
Name
Element
Atomic
Symbol
Number
Atomic Mass
# of Electrons
# of Protons
# of Neutrons
Hydrogen-1
Hydrogen-2
Hydrogen-3
___________ -35
Cl
Chlorine-37
Carbon-12
Carbon-13
153
Exit Ticket
Atom 1
12
6
C
Carbon-12
Argon-40
11
5
B
An atom with 13
protons and 13
neutrons
Atom 2
C
13
6
12
6
C
Argon-41
Boron-10
An atom with 14 protons and
13 neutrons
Relationship between atom 1 and atom 2
Isotopes
Same Atom, Not Isotopes of Each Other
Different Element
Isotopes
Same Atom, Not Isotopes of Each Other
Different Element
Isotopes
Same Atom, Not Isotopes of Each Other
Different Element
Isotopes
Same Atom, Not Isotopes of Each Other
Different Element
Isotopes
Same Atom, Not Isotopes of Each Other
Different Element
Essential Question: How can nuclei of the same element differ?