The Elements Organized

THE PERIODIC LAW

Vocabulary:

• The Periodic Law
• Chemical Property
• Physical Property
• Period
• Group or Family

Look at all the shapes below

What are some ways that you could organize them? (Think about this before you move on!)

By shape?

By shape (number of sides)?

By color?

By color?

By number order?

By number order?

By relative size?

By relative size?

By color intensity?

By color intensity?

Organization

• If you look at all the previous organization slides, you will start to see patterns within the patterns. In other words, there are relationships between the different properties of the shapes. Shape, number, color, shade, number of sides, size all have some related patterns.
• So how could we best organize the shapes to show ALL of those relationships. Look at the next slide and think hard about that.

How can these shapes be best organized to show as many relationships in the properties of the shapes?

Do you see ALL the patterns now?

Do you see ALL the patterns now?

The numbers are in order from left to right, top to bottom.

Do you see ALL the patterns now?

The color group is the same in each column.

Do you see ALL the patterns now?

The color changes in the same way from left to right (rainbow order).

Do you see ALL the patterns now?

The shade of the color gets darker as you go down a column.

Do you see ALL the patterns now?

The type of shape is the same in each column.

Do you see ALL the patterns now?

The number of sides on the shapes roughly increases from left to right.

Do you see ALL the patterns now?

The size of the shapes decreases from left to right.

When everything was disorganized, it was very difficult to see any order or patterns.

But when the shapes were placed in number order, the properties of the shapes repeated periodically. We can see this repeating of properties on each row.

There’s another group of things where order appears out of disorder when properties are organized.

The Periodic Table!

Dmitri Mendeleev

• In the mid 1800’s, a Russian science teacher named Dmitri Mendeleev was working with the roughly 56 known elements and identifying the elements’ physical and chemical properties.

What are Physical Properties

• An attribute of a substance that can be observed or measured without changing the composition of matter.
• Physical properties are used to observe and describe matter.

Physical Properties

• Examples:
• texture, color, odor, melting point, boiling point, density, solubility, magnetism, and many others.

What are Chemical Properties

• A characteristic or behavior of a substance that may only be observed when it undergoes a chemical change or reaction. Chemical properties are all about how a substance interacts with other substances.

Chemical Properties

• Examples: flammability, reactivity with acids, and toxicity.

Dmitri Mendeleev

• Mendeleev began seeing patterns and trends in the physical and chemical properties of the elements, properties that he started using to organize the elements.

Dmitri Mendeleev

• “I saw in a dream a table where all elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper, only in one place did a correction later seem necessary.”

The Periodic Law

• Mendeleev organized the elements using very similar methods that we did with the shapes earlier in this presentation. He placed the elements in atomic mass order and saw that the chemical and physical properties of the elements repeated periodically.
• For example, lithium, sodium and potassium are all soft, shiny, very reactive elements.

The Periodic Law

• So he made rows of these repeating patterns which then created columns of elements with similar properties.

The Periodic Law

• So he made rows of these repeating patterns which then created columns of elements with similar properties.

The Periodic Law

• So he made rows of these repeating patterns which then created columns of elements with similar properties.

The Periodic Law

• So he made rows of these repeating patterns which then created columns of elements with similar properties.

The Periodic Law

• So he made rows of these repeating patterns which then created columns of elements with similar properties.

The Periodic Law

• So he made rows of these repeating patterns which then created columns of elements with similar properties.

The Periodic Law

• The Periodic Law: the elements, when listed in order of their atomic numbers (originally, atomic weights), fall into recurring groups, so that elements with similar properties occur at regular intervals.

Mendeleev’s Original Periodic Table Organization

Periods

• Rows on the periodic table are called periods because the properties of the elements repeat periodically.
• Each new row is the beginning of those repeating properties.
• The periods are numbered 1 – 7 from top to bottom on the periodic table.

Groups (Families)

• Columns on the periodic table are called groups or families because the elements in each column have very similar physical and chemical properties.
• The groups are numbered 1 – 18 across from left to right on the periodic table.

Groups (Families)

• The groups have names that you need to be familiar with:

Groups (Families)

• The groups have names that you need to be familiar with:

Group 1: Alkali Metals

Groups (Families)

• The groups have names that you need to be familiar with:

Group 2: Alkaline Earth Metals

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 3-12: Transition Metals

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 13: Boron Family

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 14: Carbon Family

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 15: Nitrogen Family

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 16: Chalcogens

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 17: Halogens

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 18: Noble Gases

Groups (Families)

• The groups have names that you need to be familiar with:

Groups 18: Noble Gases

Metals

Elements left of the stairstep line but not touching it (exceptions: H-nonmetal, Al-metal, and Po-metal)

Properties: � ◦ shiny� ◦ conduct heat and electricity� ◦ malleable and ductile� ◦ mostly hard solids

Metals

Nonmetals

• Elements right of the stairstep line but not touching it (exception: At)
• Properties:� ◦ dull� ◦ nonconductors� ◦ brittle� ◦ variety of states of matter

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Nonmetals

Metalloids

• Most elements touching the stairstep line.
• Properties:� ◦ between metals and � nonmetals

Metalloids