Atomic Structure And Periodic Table Flashcards
What are atoms
They are subatomic particles (protons,neutron and electron)
What is an atoms diameter
(1x10^_10 metres)
What is the size of a nucleus in relative to the atom
1/10000
Relative charge and relative mass of each subatomic particle
Proton: charge+1 - mass 1
Neutron: charge 0 - mass 1
Electron: chareg -1 - 0
Why do atoms have no electrical charge
Number of protons equal to number of electrons
How to find mass number of an element
Number of protons + neutrons
How to find atomic number of an element
Number of protons or electrons
How to electrons orbit the nucleus and give the formation
Orbit shells in fixed distances from the nucleus
First shell is 2 with every subsequent electron shell having a max number of 8
What are atoms with incomplete outer shells and what happens during a reaction
They become unstabled and when they react they gain a complete outer electron shell
Explain the early concepts of atomic theory
What they are?
When?
Founder?
Small,indivisible,spherical atoms
19th century
John Dalton
Explain the plum pudding model
What is it?
When?
Founder?
Solid proton sphere with electrons embedded inside it
1904
JJ Thomson
Explain the nuclear model
What is it?
Date?
Founder?
Tiny, dense indivisible positive nucleus, surrounded by negative electrons
1911
Ernest Rutherford
What is the orbital model?
Date?
Founder?
Tiny,dense, indivisible positive nucleus, orbited by electrons in fixed shells
1913
Niel Bohr
What is the modern atomic structure
What is it?
Date?
Founder?
Tiny central nucleus (made of protons and neutrons) orbited by very tiny negative electrons
1926
John Dalton
Explain the alpha particle scattering experiment
Theory
Alpha partciles (positively charged- large mass) should pass straight through the gold foil and be detected other side.
This is due to weak, positive,solid atoms in the Plum pudding model have neither a sufficient density to resist the radiation or a strong positive charge to deflect it
Explain the alpha particle scattering experiment
What happened during the experiment
Positive alpha particles shot at the gold foil
Radiation did not pass through the gold foil but was significantly deflected and some were reflected to the radiaoactive material
What did Rutherford conduct from the experiment
1) Alpha particle passes striaght through the foil without colliding into anything (reflected/deflected). This indicates there is lots of empty space in the atom (mostly)
2) Alpha radiation is deflected through the foil. This shows that the positively charged alpha particles are being repelled by another positive charge. This shows that the atom must have a tiny central nucleus that has a strong posiitve charge.
3) Alpha particles is reflected back to the source. The relatively heavy alpha radiation bounces back of the nucleus. This shows that the nucleus must be very dense.
What is an isotope
Atoms of the same element with the same amount of protons but different number of neutrons
How to calculate relative atomic mass
Relative atomic mass= (% isotope 1 x Mass isotope 1) + (%isotope 2 x Mass isotope 2)
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Sum of all isotope abundance
What are the starting chemicals called
Reactants
What is the name of chemical that are made in a reaction
Products
What happens to the atoms during a chemical reaction
Reactants bond are broken and new chemical bonds made to form the products. Atoms are unchanged , only bonding changes.