Unit 2 – Lesson 5 (The Periodic

Table)

What are Elements?

• People once believed that everything was made up of different combinations or Earth, Wind, Fire, and Water

• By the 1860s, scientists considered there to be at least 60 different basic substances, or elements.

How are the Elements Organized?

• Dmitri Mendeleev was the first scientist to put the elements in order of increasing mass. When he arranged them this way, a regular pattern, or periodic pattern emerged.

• Mendeleev’s arrangement was called the Periodic Table.

What information is contained in each square on the Periodic Table

• Atomic Number, Chemical Symbol, Chemical Name, Average Atomic Mass

• How do you get Gold’s attention?

What information is contained in each square on the periodic table?

• Chemical Symbol: an Abbreviation for the element’s name.

• Average Atomic Mass: the weighted average of the masses of all naturally occurring isotopes of that element

How are the elements arranged on the Periodic Table?

• Metals, Nonmetals, and Metalloids are found in Three Distinct Regions.• Metals: Elements that are shiny and conduct heat and

energy well

• Nonmetals: Poor conductors of heat and electricity

• Metalloids: Elements that have some properties of metals and some properties of nonmetals

How are the Elements Arranged on the Periodic Table?

• Elements in each column have Similar Properties.

• Each vertical column is known as a Group.

• Similar because of the number of valence electrons.

How are the Elements Arranged on the Periodic Table?

• Elements in each row follow Periodic Trends. Therefore, they are known as Periods.

How are the Elements Arranged on the Periodic Table?

• Elements are Arranged in Order of Increasing Atomic Number.