Elements
What elements symbol is He?
Helium
What are elements classified as? (there are three)
Metals, metalloids, and nonmetals
What year did Dmitri Mendeleev discover the table?
1869
What is an another name for groups?
families
What is another name for periods?
rows
How many elements are there today?
118
How did Dmitri Mendeleev organize his table?
atomic mass
How many groups are there?
18
How many periods are there?
7
What is the number of electrons and neutrons based on?
The atomic number
True or False: The elements in each group have the same number of valence electrons.
True
Why the the elements in each row grouped that way?
number of shells
Why would you use this: the mass minus the atomic number.
number of electrons
When did Dmitri pass away?
1907