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Unit 2: Atomic Structure

Atomic Structure and Periodic Table Key Learnings Chemistry Standard/Outcome

1 Atomic Structure

2 Isotopes

3 Periodic Families

4 Metals and Non-metals

Atomic Structure Skills

Be able to describe the charge, location, and relative mass of the electron, proton, and neutron

Be able to use a complete atomic symbol, (for example 𝐹919 ), to identify the number of

electrons, protons and neutrons in an atom.

Be able to use an isotope symbol, (for example Flourine-19) to identify the number of electrons, protons and neutrons in an atom.

Be able to determine if two elements are isotopes of each other.

Be able to calculate the average atomic mass given the relative abundance and mass of the isotopes

Know the importance of protons in identifying an element.

Periodic Table Skills

Be able to identify an element based on group and period

Be able to identify the location of periodic families.

Be able to determine if an element is a metal non-metal or metalloid.

Keywords

Nucleus

Proton

Neutron

Electron

Subatomic particle

Atomic number

Mass number

Isotope

Group

Period

Alkali metals

Alkaline earth metals

Transition metals

Halogens

Noble gases

Actinides

Lanthanides

Inner transition metals

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Atomic Structure Unit

Date Topic

9/9 Color Coding the Periodic Table

9/12 Structure of the Periodic Table Notes and Practice

9/13 Atomic Structure Notes and Practice

9/14 Atomic Structure Practice

9/15 WebAssign

9/16 Introduction to Isotopes Notes

9/19 Isotopes Practice

9/20 Isotopes Practice

9/21 Average Atomic Mass Notes

9/22 Average Atomic Mass Practice

9/23 Isotopes of Pennies Lab

9/26 Atomic Structure Unit Review, Short Answer Practice

9/27 Atomic Structure Unit Test

9/9/15 Objective: Students will use the structure of the periodic table to describe elements. Warm-Up:

1. What are two things I want you to know when you complete this unit?

2. When is your unit test?

9/12/15 Objective: Students will use the structure of the periodic table to describe elements. Warm-Up:

1. What is the difference between a group/family and a period?

2. What family is Se in? Period?

3. Is Se a metal, metalloid, or non-metal?

The Periodic Table of Elements

The periodic table organizes the elements in a particular way. A great deal of information about an

element can be gathered from its in the periodic table.

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For example: you can predict with reasonably good accuracy the and chemical

properties of the element. You can also predict what other elements a particular element will

with chemically.

Understanding the and of the periodic table

will help you obtain basic information about each of the 118 known elements.

The elements on the periodic table can be divided into three main categories: metals, non-metals, and

metalloids.

Properties of metals

o Metals are good conductors of and

o Metals are

o Metals are (can be stretched into thin wires).

o Metals are (can be pounded into thin sheets).

o A chemical property of a metal is its reaction with water which results in .

Properties of Non-Metals

o Non-metals are conductors of heat and electricity.

o Non-metals are not or .

o Solid non-metals are and break easily.

o They are .

o Many non-metals are .

Properties of Metalloids

o Metalloids (metal-like) have properties of both and .

o They are that can be shiny or dull.

o They conduct heat and electricity better than non-metals but not as well as metals.

o They are and .

Elements in the periodic table are also grouped into families ( ) and periods (

).

Families:

o of elements are called groups or .

o Elements in each family have but not identical properties.

o For example: Lithium (Li), Sodium (Na), Potassium (K), and other members of family IA are all

soft, white, shiny metals.

o All elements in a family have the same number of .

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Periods:

o Each row of elements is called a .

o The elements in a period are in properties.

o In fact, the properties change greatly across a given row.

o The first element in a period is always an solid. The last

element in a period, is always an .

Families

o The hydrogen square sits atop Family Al, but it is not a member of that family. Hydrogen is a

class of its own.

o It’s a gas at room temperature.

o It has one proton and one electron in its one and only energy level.

o Hydrogen only needs 2 electrons to fill up its valence shell.

o The Alkali family is found in the first column of the periodic table.

o Atoms of the alkali metals have a single electron in their outermost level, in other words, 1

valence electron.

o They are shiny, have the consistency of clay, and are easily cut with a knife.

o They are the most reactive metals.

o They react violently with water.

o Alkali metals are never found as free elements in nature. They are always bonded with another

element.

o They are never found uncombined in nature.

o They have two valence electrons.

o Alkaline Earth metals include magnesium and calcium, among others.

o Transition elements include those elements in the B families.

o These are the metals you are probably most familiar: copper, tin, zinc, iron, nickel, gold and

silver.

o They are good conductors of heat and electricity.

o The compounds of transition metals are usually brightly colored and are often used to color

paints.

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o Transition elements have 1 or 2 valence electrons, which they lose when they form bonds with

other atoms. Some transition elements can lose electrons in their next-to-outermost level.

o Transition elements have properties similar to one another and to other metals, but their

properties do not fit in with those of any other family.

o Many transition metals combine chemically with oxygen to form compounds called oxides.

o The Boron family is named after the first element in the family.

o Atoms in this family have 3 valence electrons.

o This family includes a metalloid (boron), and the rest are metals.

o This family includes the most abundant metal in the Earth’s crust (aluminum).

o Atoms of this family have 4 valence electrons.

o This family includes a non-metal (carbon), metalloids, and metals.

o The element carbon is called the “basis of life.” There is an entire branch of chemistry devoted

to carbon compounds called organic chemistry.

o The nitrogen family is named after the element that makes up 78% of our atmosphere.

o This family includes non-metals, metalloids, and metals.

o Atoms in the nitrogen family have 5 valence electrons. They tend to share electrons when they

bond.

o Other elements in this family are phosphorus, arsenic, antimony, and bismuth.

o Atoms of this family have 6 valence electrons.

o Most elements in this family share electrons when forming compounds.

o Oxygen is the most abundant element in the earth’s crust. It is extremely active and combines

with almost all elements.

o The elements in this family are fluorine, chlorine, bromine, iodine, and astatine.

o Halogens have 7 valence electrons, which explains why they are the most active non-metals.

They are never found free in nature.

o Halogen atoms only need to gain 1 electron to fill their outermost energy level.

o They react with alkali metals to form salts.

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o Noble Gases are colorless gases that are extremely un-reactive.

o One important property of the noble gases is their inactivity. They are inactive because their

outermost energy level is full.

o Because they do not readily combine with other elements to form compounds, the noble gases

are called inert.

o The family of noble gases includes helium, neon, argon, krypton, xenon, and radon.

o All the noble gases are found in small amounts in the earth's atmosphere.

o The thirty rare earth elements are composed of the lanthanide and actinide series.

o One element of the lanthanide series and most of the elements in the actinide series are called

trans-uranium which means synthetic or man-made.

9/13/15 Objective: Students will be able to identify the number of subatomic particles and the mass of an element using the periodic table. Warm-Up:

1. Why are the Alkali Metals so reactive?

2. Identify what family and period the following elements are in:

a. Li

b. Br

c. Ne

3. What element is in Group 4A or 14 and Period 6 on the Periodic Table?

The Structure of an Atom Structure of an Atom

charged (electrically charged)

o Contains almost all the of an atom

o Small but very dense

o Contains (+) and (0)

o Protons have a relative mass of

o Neutrons have a relative mass of

o Neutrons are very hard to detect in an atom

charged cloud around the nucleus (electrically charged)

o Contains

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o Arranged in various and

The very outermost shell is called the

must equal !

o This means the number of must equal the number of .

Definition of an element

o An element is defined by the number of it has. (This is what gives the

element its identity)

o Protons are smaller than electrons, but they have more mass.

o Label the following diagram.

Atomic Mass

o The Atomic weight rounded to a whole number

The sum of and

Number of neutrons = -

Ex: Mg

Atomic #:

Atomic Mass:

# of Neutrons:

9/14/15 Objective: Students will be able to identify the number of subatomic particles and the mass of an element using the periodic table. Warm-Up:

1. What subatomic particle has the highest mass? Lowest mass?

2. What subatomic particles are electrically charged? What is their charge?

3. Where are the electrons located in an atom? The protrons?

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9/15/15 Objective: Students will be able to identify the number of subatomic particles and the mass of an element using the periodic table. Warm-Up:

1. Which subatomic particle is responsible for the identity of the element?

2. Which element has the atomic #18? What group and period is it in? Is it a metal, metalloid, non-metal?

3. List 4 other elements that share similar properties as the element in #2.

Vocabulary Builder

Define the following vocabulary words. Then, write a sentence using the word but instead of writing the

word, draw a picture in its place.

EXAMPLE

Word: Noble Gases Definition: The elements in group 8A or 18 including Helium, Neon, Argon, Krypton, Xenon, and Radon.

Sentence: The are called noble because they contain 8 valence electrons and do not react with other

elements.

Word: Nucleus

Definition:

Sentence:

Word: Proton

Definition:

Sentence:

Word: Neutron

Definition:

Sentence:

Word: Electron

Definition:

Sentence:

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Word: Atomic Number

Definition:

Sentence:

Word: Mass Number

Definition:

Sentence:

Word: Group

Definition:

Sentence:

Word: Period

Definition:

Sentence:

9/16/15 Objective: Students will distinguish between different isotopes of an element and determine the number of subatomic particles. Warm-Up:

1. Which element has 32 protons, 32 electrons, and 41 neutrons?

2. What family and period is this element in?

3. List 4 more elements in the same period as the element in #1.

Isotopes

Is an atom with the number of protons but number of neutrons

o Isotopes are of the same atom!

How to Write an Isotope

o 2 ways

-

Ex:

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Element Notation (copy the diagram here )

Ex:

Finding Neutrons:

o Find the of the element and subtract if from the new

.

Ex: Carbon-12

Ex:

The Same Properties

o Because an isotope is a of the same atom, all isotopes have

, because they are all forms of the same thing!!

o The number of and is the same! Only the

number of change!

9/19/15 Objective: Students will distinguish between different isotopes of an element and determine the number of subatomic particles. Warm-Up :

1. What does the following element description actually mean?

2. An element has 22 protons, 22 electrons, and 28 neutrons. Identify this element using both ways to

write an isotope.

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9/20/15 Objective: Students will distinguish between different isotopes of an element and determine the number of subatomic particles. Warm-Up :

1. Use the following t-charts to compare and contrast the subatomic particles.

Protons and Neutrons Protons and Electrons Neutrons and Electrons

Similarities Differences Similarities Differences Similarities Differences

9/21/15 Objective: Students will calculate the average atomic mass of common isotopes of an element. Warm-Up:

1. What do the following element descriptions actually mean? (think about how many subatomic particles

they have, how they are different or similar, etc.)

a. Silicon-28

b. 2. If a neutral element has the following chemical notation, how many electrons does it have? Chlorine-34

Average Atomic Mass

• All elements exist as a of .

• : how commonly an isotope is found in nature.

• Since all elements exist as a collection of isotopes, we need to find the average atomic mass of the

element in order to use it for calculations.

• The average atomic mass of an element is the of the masses of its isotopes each

by its natural abundance.

• Average Atomic Mass is a !

Calculating Average Atomic Mass

1. Change the percent abundance to a

2. the decimal amount by the mass number.

3. Repeat steps 1 and 2 for all isotopes.

4. the answers together to get the average atomic mass.

5. The unit is , atomic mass unit.

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Example:

Nitrogen-14 99.63%

Nitrogen-15 0.37%

Example:

Lithium-6 7.5%

Lithium-7 92.5%

Example:

Magnesium-24 78.99%

Magnesium-25 10.00%

Magnesium-26 11.01%

9/22/15 Objective: Students will calculate the average atomic mass of common isotopes of an element.

Warm-Up:

1. Calculate the average atomic mass of the following element.

a. 32X – 95.02%

b. 33X – 0.75%

c. 34X – 4.21%

d. 36X – 0.02%

2. Identify the element in the previous problem.

3. What family and period is this element in? Is it a metal, metalloid, or non-metal?

4. List 3 other elements with the same properties as the element in #1.

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9/23/15 Objective: Students will calculate the average atomic mass of common isotopes of an element.

Warm-Up:

1. The average atomic mass of Titanium is 47.867amu. One isotope of Titanium has a mass of 47, the

other has a mass of 48. Which isotope is more common in nature? Explain why.

9/26/15 Objective: Students will demonstrate their knowledge of atomic structure on a unit review. Warm-Up: Short Answer Practice 9/27/15 Objective: Students will demonstrate their knowledge of atomic structure on a unit test. Warm-Up: None