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.