Topic 1.1- Key concepts Flashcards
Atomic structure, Periodic table
How has the dalton model changes over time?
Dalton, Plum and pudding, Nucleur
2) - Dalton believed atoms couldn’t be broken down
1) - Plum Pudding: Thompsons discovers electrons and experiments with cathode rays( high speed electrons, repelled from cathode which is also negative) proved negatively charged electrons
3) -Nuclear model: Rutherford gold foil experiment discovered a** positively** charged nucleus and is mostly empty space (Many stright through—>empty space, Some deflected —-> small positive centre/nucleus)
4) Rutherford suggested NUCLEAR MODEL (orbits in fixed shells with protons in nucleus)
Why do atoms contain the same number of electrons and protons?
For it to have neutral charge
How much smaller is the nucleus of an atom compared to the size of the atom?
100,000 times smaller
What is the mass of a neutron and proton?
1
What is the mass of an electron?
1/1836
what does mass of an atom mean?
the sum of individual particles (neutrons and protons)
in terms of hydrogen
What is an isotope?
-Same electrons and protons
-Different number of neutrons
-Affects mass
What is the atomic number?
The number of protons
How is the periodic table organised?
Increasing atomic number
How to calculate relative atomic mass?
(mass x abundance) + (mass x abundance)…
——————————-
Total abundance
How big is an atom
0.1 nm radius
How did Mendeleev arranged the elements?
Rows by increasing atomic mass
How was Mendeleev able to predict the existence and properties of new substances?
- Noticed every eighth element had same properties as the first, made rows of seven
- Left gaps when atoms didn’t fit in a group
What was wrong about Mendeleev’s organisation?
Atomic mass didn’t take into account:
-Relative atomic mass
-Isotopes
What are the rows called? And what do these mean?
Periods, number of rings/orbitals.
