Ch. 4 – The Periodic Table

Today’s Assignment• Read pgs. 104-105 and make your

own notes.• Do Activity 4.3 on page 108-109.

Do all parts of the procedure and hand in by the end of class.

• If you finish early do Understanding Concepts (pg. 109) ques. 1-4 & 6.

Groups of Elements• The periodic table is arranged so that

elements with similar properties are in groups.

• There are groups with specific names on the table. These groups are named because the elements in these groups have extraordinary properties.

Video

A Family is also called a Group.

based on their atomic numbers.

Groups or Families

• 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 electrons in their outer orbital.

• 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.

• The period tells us how many orbitals the element has.

Periods

Noble Gases

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

• One important property of the noble gases is their inactivity. They are inactive because their outermost energy level is full.

• Because they do not readily combine with other elements to form compounds, the noble gases are called inert.

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

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

Alkali Metals

• These metals are highly reactive and readily form compounds with other elements. Most commonly H, O, Cl, F, Br, I.

• The reactivity of alkali metals is explained by their structure. These metals have only one electron in their outer orbital. They will readily lose this electron to become a stable atom.

The alkali metals (group 1A) are located in the far left column of the periodic table.

Halogens

• They make very useful compounds such as iodized table salt, chlorine in drinking water, sodium fluoride in toothpaste, etc.

• The reactivity of halogens is explained by their structure. These non metals need only 1 electron to fill their outer orbital. They will readily gain this electron to become a stable atom.

• Group VII A • Include F, Cl, Br, I, At• Next to the noble gases• These are the most

reactive non metals. They almost always appear naturally as compounds (Cl2, Br2 , etc.)

A Group of One• Hydrogen is a unique element.

• It has only 1 electron. Therefore it has only one orbital (How many electrons can this orbital hold?)

• It can react as both a metal and a non metal. It can either lose or gain 1 electron to become a stable atom.

• Most of the Earth’s hydrogen exists in compounds due to it’s high reactivity.

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 brittle and not ductile

• Metalloids have some characteristics of both metals and nonmetals. They are B, Si, Ge, As, Sb, Te, Po.

• How to tell metals from nonmetals: B

Al Si Ge As

Sb Te

Po At These are the purple elements on the periodic table in your textbook.

Assignment

• Read pgs. 110 – 113

• Understanding Concepts pg. 113; answer questions 1 – 10.