What did people used to think matter was made up of?
Earth, air, fire, and/or water.
What are elements?
Substances made up of only one kind of matter.
Why do scientists call elements "the building blocks of matter?
Because they can't be broken down into a simpler form.
Name three elements.
Wow, you really know your stuff! / Sorry, we were looking for...
What two main categories do scientists classify elements into?
Metals and nonmetals. (also: gases)
How is the periodic table organized?
By atomic number.
Why are there blank spaces on the periodic table?
Scientists haven't found all the elements they predicted yet.
Who's this? What's he famous for?
Dmitri Medeleev; he invented the periodic table.
Name two properties scientists use to classify elements.
Magnetism, reactivity, mass, conductivity, etc.
How is it possible to make predictions about elements that haven’t been discovered yet?
By looking at the properties near to their position of the periodic table.
