Periodic table Flashcards
How are the groups arranged in their periodic table?
according to their properties
How can you tell that the alkali metals are very reactive?
according to their properties (the reaction with water)
How can you tell the noble gases are unreactive?
full shell of the outer electron (does not readily form compounds)
Describe the plum pudding model of the atom
A sphere of positive charge with electrons dotted about
Who made the plum pudding model?
JJ Thompson
Why did scientists not believe the plum pudding model
lack of experimental evidence
Niels Bohr discovered that…
electrons orbit the nucleus in shells
Why did Mendeleev leave gaps in the periodic table
he knew elements existed but weren’t found (they were based on their mass)
What happened to some of the gaps he left?
the have been filled with scientist that have found some of the elements
How were the elements arranged?
Atomic mass
