the periodic table Flashcards
1
Q
what are periods?
A
rows
2
Q
what are groups?
A
columns
3
Q
elements on the same group have the ____ number of outer shell electrons. Therefore they have similar _________.
A
same number of outer electrons
similar properties
4
Q
how was the early periodic table ordered by?
A
atomic weight
5
Q
was the early periodic table complete or incomplete? why?
A
incomplete
, not all elements were discovered
6
Q
in the early periodic table, was the elements in groups of similar properties?
A
no
7
Q
how is the modern periodic table ordered by?
A
atomic number
8
Q
what are 2 things that Mendeleev did to the periodic table?
A
left gaps for undiscovered elements
changed order from atomic weight to groups of similar properties
