Decoding
The Periodic Table
Identify A, B, C and D in the Periodic Table box:
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https://docs.google.com/document/d/1nO8jcx5uLjsFZRb5KXowxDjkvQlUAfnzW0j6CKwsLVE/edit?usp=sharing
A. Atomic number
B. Element symbol
C. Element name
D. Atomic mass
2CH4 (methane)
Identify the subscript above in the methane molecule. What is it and what does it tell you?
Subscript = 4 (it indicates there are four H atoms in every molecule of methane, CH4)
Name the subatomic particles, where they are, and what their charges are.
Protons (+) and neutrons are inside the nucleus.
Electrons (-) are in the electron cloud.
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What is a neutral atom?
What is an ion?
What is an isotope?
A neutral atom does not have a charge. #e = #p
An ion is a charged particle.
Neg. charge if #e >#p Pos. charge if #p >#e
Isotopes are atoms of the same element with different masses. For example: 1H 2H 3H
Where are the metals, nonmetals and metalloids located in The Periodic Table?
The metals are on the left side and center of The Periodic Table.
The nonmetals are on the right side of The Periodic Table.
The metalloids are in between the metals and nonmetals.
How many protons, electrons and neutrons in the element shown?
Explain how you found the number of protons, electrons and neutrons.
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Protons = 9 (the atomic number tells you this)
Electrons = 9 (the atomic number tells you this. If there is no charge, then the atom is neutral and the #p = #e)
Neutrons = 10 (the atomic mass minus the atomic number tells you this)
2C18H28O2
Identify the coefficient above in the testosterone molecule. What is it and what does it tell you?
Coefficient = 2 (it indicates the number of methane molecules)
1C18H28O2 = C18H28O2
2C18H28O2 = C18H28O2 + C18H28O2
3C18H28O2 = C18H28O2 + C18H28O2 + C18H28O2
Draw a Bohr model of a carbon atom.
Go to: https://docs.google.com/document/d/1nO8jcx5uLjsFZRb5KXowxDjkvQlUAfnzW0j6CKwsLVE/edit?usp=sharing
In the nucleus, 6 protons and 6 neutrons.
In the 1st energy level of the electron cloud, 2 electrons.
In the 2nd energy level of the electron cloud, 4 electrons.
Match the following:
e=electron p=proton n=neutron
a. #e = #p 1. ion
b. #p is the same but #n changes 2. neutral atom
c. #e does NOT = #p 3. isotope
a. ------- 2.
b. ------- 3.
c. ------- 1.
What is malleable?
What is ductile?
What is conductivity?
Malleable = ability to be flattened into sheets of metal or other shapes.
Ductile = ability of a metal to be pulled into a wire.
Conductivity = ability of an object to transfer heat or electricity to another object.
What are periods, groups and families on The Periodic Table? And how are they numbered?
The horizontal rows = periods (there are seven numbering from 1, at the top, to 7, at the bottom).
The vertical columns are groups or families. There are 18 across the top, but in 7th grade we number them as "1, 2, skip a few (the transition metals), 3, 4, 5, 6, 7 and 8."
In an atom, where is most of the mass of that atom located?
In an atom, where is most of the volume of that atom?
Most of the mass is in the nucleus. Remember, p+ and n each have a mass of 1 amu (atomic mass unit).
Most of the volume of an atom is in the electron cloud. (baseball stadium analogy)
Identify the atom in the picture.
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https://docs.google.com/document/d/1nO8jcx5uLjsFZRb5KXowxDjkvQlUAfnzW0j6CKwsLVE/edit?usp=sharing
Lithium, 7Li
Identify the following as either an anion or cation:
1. a negatively charged particle
2. a positively charged particle
3. a particle with more protons than electrons
4. Br- and N-3 and O-2
1. anion
2. cation
3. cation
4. all anions
Where are the Alkali Metals, Alkaline Earth Metals and Transition Metals on The Periodic Table?
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https://docs.google.com/document/d/15bcqCad2nJu7yS4FDvpqP2E8BAQBsm097q2O8C4-8Uo/edit?usp=sharing
Alkali Metals are in group 1 - colored red.
Alkaline Earth Metals are in group 2 - blue/purple
Transition Metals are to the right of groups 1 and 2 - blue
What is the mass number?
How do you identify it in a Periodic Table box?
Mass number = #protons + #neutrons (in the nucleus)
Find the Atomic Mass. Round it to the closest whole number and THAT is the mass number.
Bohr models are fun to draw, ...
But, a simpler and faster way to show how many valence electrons are in an atom is with an Electron Dot Diagram.
Draw Electron Dot Diagrams for all the atoms on the Review Questions Sheet.
Go to: https://docs.google.com/document/d/1wJgNcIrKzhtLQ1L9bJ1wJK_A34nwvECRLny2LPNzzDk/edit?usp=sharing
Go to the practice sheet.
What is the maximum number of electrons that each energy level can hold?
The 1st energy level (closest to the nucleus) holds ___ electrons.
The 2nd energy level holds ___ electrons.
The 3rd energy level holds ___ electrons.
The 1st energy level holds _2_ electrons.
The 2nd energy level holds _8_ electrons.
The 3rd energy level holds _8_ electrons.
1. Why would a sodium atom want to give away its 1 valence electron?
2. And, why is a chlorine atom a perfect recipient of sodium’s dropped valence electron?
3. What does sodium and chlorine make when they bond together?
Go to: https://docs.google.com/document/d/15bcqCad2nJu7yS4FDvpqP2E8BAQBsm097q2O8C4-8Uo/edit?usp=sharing
1. To have a complete outermost energy level.
2. Because chlorine has 7 valence electrons and needs 1 more electron to complete its outermost energy level.
3. Sodium + Chlorine = NaCl = table salt
What state of matter are most of the nonmetals at room temperature?
10 of the 16 nonmetals are gases. Most of the gas we breathe is made up of Nitrogen and Oxygen, gases at room temperature.
How do the group/family numbers in The Periodic Table relate to the number of valence electrons?
What group number are carbon, silicon and lead in?
How many valence electrons do C, Si and Pb have?
The group/family number is the number of valence electrons for every element in that family.
C, Si and Pb are in group # 4.
C, Si and Pb all have 4 valence electrons.
Use electron dot diagrams for Na and Cl to show how salt is made.
Dr. Collins will demonstrate on the White Board.
When an atom's outermost energy level is full it is stable.
Look at the Bohr models for He, Ne and Ar. What do you notice?
Go to:
https://docs.google.com/document/d/1nO8jcx5uLjsFZRb5KXowxDjkvQlUAfnzW0j6CKwsLVE/edit?usp=sharing
All of these atoms have an outermost energy level that is full. Therefore, all of these atoms are stable.
They are all in the Noble Gas family, group #8, and they do not react with other atoms readily.
Why would a neutral atom like beryllium (Be) want to become an ion (Be+2)?
In other words, why would an atom that has p+= e- want to lose or gain electrons so p+ does not = e- ?
All atoms want to have a complete outermost energy level of electrons. When they have that, they are stable.
They are stable like the Noble Gases, group #8.
Why are metalloids so useful in electronics and, in particular, computers, cell phones, etc.?
Metalloids are semiconductors, in other words, they conduct electricity in certain conditions and not in others. Temperature, light, and the presence of impurities can affect whether metalloids conduct electricity.