Atomic Structure and the Periodic Table Flashcards
Define compund
A compound is two or more elements chemically joined together
Define mixture
A mixture is two or more elements not chemically joined together
History of the atom - 1800’s
- John Dalton says that the atom is a solid sphere
- JJ Thompson discovers the electron and creates the plum pudding model
Describe the plum pudding model
It said that the atom was a solid sphere of positive charge with negatively charged electrons randomly scattered across it
What happened after the plum pudding model
Rutherford conducts the gold foil experiment and discovers the nucleus
Describe the gold foil experiment
Rutherford shot alpha particles at a sheet of gold foil. Most of the particles went straight through, but some were deflected by the gold foil
What did the gold foil experiment tell Rutherford
It told him that the atom had to have a centre of positive charge as the particles deflected of the foil. It also told him that the atom was mostly empty space as the particles went through
What did Neil Bohr do
Bohr suggested that the electrons orbited the nucleus at specific distances. He also mad the Bohr model
What does the mass number represent
The number of protons and neutrons added together
What does the atomic number suggest
The number of protons and electrons
What did John Newlands do
He ordered his periodic table in atomic mass
What did Dmitri Mendeleev do
He also ordered his table in atomic mass but left gaps for elements that were not discovered
What happens when group 1 metals react with chlorine
They form a white precipitate
What is the trend going down group 1
The reactivity increases
What is the trend going down group 0
Boiling point increases
