History of the Periodic Table

Front

What are metalloids?

Back

Elements that have properties of both metals and nonmetals.

Front

What are metals known for?

Back

Good conductors of heat and electricity.

Front

What are nonmetals characterized by?

Back

They are dull and brittle.

Front

What does the dark line between La & Hf and Ac & Rf indicate?

Back

It indicates the series of elements would be at that location if there were enough room.

Front

Which element has an atomic mass less than twice its atomic number?

Back

Oxygen.

Front

What is the significance of the periodic table?

Back

It organizes elements based on their atomic number and properties.

Front

What are the three main categories of elements in the periodic table?

Back

Metals, nonmetals, and metalloids.

Front

What is the atomic number?

Back

The number of protons in the nucleus of an atom.

Front

What is the atomic mass?

Back

The weighted average mass of an element's isotopes.

Front

What are alkali metals?

Back

Highly reactive metals found in Group 1 of the periodic table.