Answer:
Ar
Explanation:
does not react with anything it has a full electron shell so it does not combine and it is a noble gas
Answer:
D. They react readily with oxygen in the air
Answer:
Dmitri Mendeleev
used patterns to predict undiscovered
elements
Johann Wolfgang Dobereiner
created groups of three elements,
each based on similar properties
John Newlands
arranged elements according to their
atomic mass
Antoine Lavoisier,
divided elements into four categories
✓
