Monday, Sept. 15th

Do Now

As you know, elements are arranged by their

properties on the periodic table. What other objects

are often arranged by their properties?

The Periodic TableHow the periodic table is put

together

What do all the numbers mean ?

From www.science-class.net

What is the Periodic Table?

It is an organizational system for elements.

Picture from www.chem4kids.com

Who created it? The quest for a systematic

arrangement of the elements started with the discovery of individual elements.

  By 1860 about 60 elements were known and a method was needed for organization. 

In 1869, Russian chemist Dimitri Mendeleev proposed arranging elements by atomic weights and properties.

The table contained gaps but Mendeleev predicted the discovery of new elements.

So how is it arranged?

The genius of the periodic table “is that it is organized like a big grid. The elements are placed in specific places because of the way they look and act. If you have ever looked at a grid, you know that there are rows (left to right) and columns (up and down). The periodic table has rows and columns, too, and they each mean something different.”

quoted from http://www.chem4kids.com/files/elem_pertable.html

You've got Your Periods...

Even though they skip some squares in between, all of the rows go left to right. When you look at a periodic table, each of the rows is considered to be a different period (Get it? Like PERIODic table.)

quoted from http://www.chem4kids.com/files/elem_pertable.html

Periods = Rows

In the periodic table, elements have something in common if they are in the same row.

Elements are arranged in rows by increasing atomic # All of the elements in a period have the same number

of energy rings. Every element in the top row (the first period) has one

ring for its electrons. All of the elements in the second row (the second period) have two rings for their electrons. It goes down the periodic table like that.

quoted from http://www.chem4kids.com/files/elem_pertable.html

And you got your groups…

The periodic table has a special name for its columns, too. When a column goes from top to bottom, it's called a group.

quoted from http://www.chem4kids.com/files/elem_pertable.html

Groups = ColumnsAKA Families

Elements in the same group have similar chemical & physical properties.

The elements in a group have the same number of valence electrons.

Every element in the first column (group one) has one electron in its outer shell. Every element on the second column (group two) has two electrons in the outer shell. As you keep counting the columns, you'll know how many electrons are in the outer shell.

Families Periods

Columns of elements are called groups or families.

Elements in each family have similar but not identical properties.

For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals.

All elements in a family have the same number of valence electrons.

Each horizontal row of elements is called a period.

The elements in a period are not alike in properties.

In fact, the properties change greatly across even given row.

The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas.

Properties of Metals

Metals are good conductors of heat and electricity.

Metals are shiny. Metals are ductile (can be

stretched into thin wires). Metals are malleable (can

be pounded into thin sheets).

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

Properties of Non-Metals

Non-metals are poor conductors of heat and electricity.

Non-metals are not ductile or malleable.

Solid non-metals are brittle and break easily.

They are dull. Many non-metals

are gases.

Sulfur

Properties of Metalloids

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

They are solids that can be shiny or dull.

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

They are ductile and malleable.

Silicon

What does it mean to be reactive?

We will be describing elements according to their reactivity.

Elements that are reactive bond easily with other elements to make compounds.

Some elements are only found in nature bonded with other elements.

What makes an element reactive? An incomplete valence electron level. All atoms (except hydrogen) want to have 8 electrons in

their very outermost energy level (This is called the rule of octet.)

Atoms bond until this level is complete. Atoms with few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons during bonding.

5

•very reactive metals that do not occur freely in nature

•malleable, ductile, good conductors of heat and electricity.

•can explode if they are exposed to water

ALKALI METALSALKALI METALS

From www.science-class.net

•metals

•very reactive

•not found free in nature

ALKLINE EARTH METALSALKLINE EARTH METALS

From www.science-class.net

•have properties of both metals and non-metals

•some of the metalloids are semi-conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators

METALLOIDSMETALLOIDS

From www.science-class.net

•not able to conduct electricity or heat very well

•very brittle

•Do not reflect light.

NON-METALSNON-METALS

From www.science-class.net

•"halogen" means "salt-former" and compounds containing halogens are called "salts"

•exist in all three states of matter

HALOGENSHALOGENS

From www.science-class.net

•do not form compounds easily – meaning they are nonreactive

•Happy/Inert Elements (Full outer Happy/Inert Elements (Full outer shells)shells)

NOBLE GASESNOBLE GASES

From www.science-class.net

Ted Ed Video

Reflection

Differentiate between metals, non-metals, and metalloids by providing examples and relate these groupings to something in your own lives where you have to categorize items based on certain factors. You should have three groupings. One group may have characteristics of both your first and last group.