Atomic Structure Flashcards
(24 cards)
When was John daltons atomic theory?
1805
What was John daltons atomic theory?
- all matter is made up of tiny particle called atoms
- atoms are tiny hard spheres that cannot be broken down
- atoms can’t be created or destroyed
- the atoms in an element are identical
When did JJ Thompson discover electrons?
1897
What are atoms made out of?
Protons, neutrons and electrons
What is the relative charge of protons?
+1
What is the relative mass of protons?
1
What is the relative charge of electrons?
-1
What is the relative mass of an electron?
1/1835
What is the relative charge of a neutron?
0 (no charge)
What is the relative mass of a neutron?
1
What do atoms in elements always have the same of?
Protons and electrons
Where are protons and neutrons found?
The nucleus
Where are electrons found?
In electron shells
Why does the nucleus have no charge?
There is the same number of protons and electrons and the charges cancel each other out so it has no overall charge
When did Rutherford discover most of the mass of the atom was in the nucleus?
1909
What was Rutherfords experiment?
Tiny positive particles were fired at a thin gold foil. Most particles passed through foil straight away with a few being deflected and a small number bouncing back?
How were atoms on the periodic table originally placed?
In order of the masses of their atoms
How did the periodic tables order change?
Those with similar properties were grouped together
Which number is the mass number?
The top one
When was the neutron discovered?
1932
Who discovered the neutron?
James Chadwick
What is an isotope?
An atom of the same element with the same atomic number but different mass numbers
How do we refer to a specific isotope?
By adding its mass number to the elements name
How do we work out the relative atomic mass of an atom?
Relative atomic mass= total mass of the atoms/the number of atoms
