Atomic Structure and Bonding Flashcards
Plum Pudding model
Positive spheres with negative electrons inside of them
Produced by JJ Thompson
Rutherford experiment
- fired positively charged particles at extremely thin gold foil
- most passed through but some were deflected (small number deflected backwards)
Rutherford model
Atom has tiny, positively-charged nucleus at centre and was surrounded by “cloud” of negative electrons
Most of atom is empty space
Bohr Model
Electrons were fixed in orbits (shells)
Each shell has a fixed energy
Electron mass and charge
- 0005 mass
- 1 charge
Neutron mass and charge
1 mass
0 charge
Proton mass and charge
1 mass
+1 charge
Nucleus facts
Middle of atom Contains protons and neutrons Positively-charged (due to protons) Almost all the mass of the atom Nucleus is tiny
Electron facts
Move around nucleus in shells Negatively-charged Tiny but cover a lot of space Almost no mass Size of shell determines size of atom
Why are atoms neutral?
The number of protons is equal to the number of electrons and the charge cancels out
Atomic number
Amount of protons
Mass number
Amount of protons and neutrons
Isotope facts
They are different forms of the same element
Have the same amount of atomic number but different mass number
Definition of relative atomic mass
average mass of an element’s atom when compared to its isotopes
How to work out relative atomic mass
Multiply each relative isotopic mass by their abundance
Add up,results
Divide by sum of abundance
Who made the first periodic table?
Dmitri Mendeleev
How did Mendeleev arrange the elements?
Sorted them based on their properties and put them in columns
Some element weren’t in the correct column due to him having wrong isotopes
Groups
Columns of elements with similar properties
Have the same outer shell electrons
Period
Another full outer shell is added to each element descending
Electron shell rules
Electrons always occupy shells
Lowest energy levels are always filled first
Only certain amount of electrons are allowed in each shell (2882)
Definition of ion
Atom that has lost or gained electrons
They have charge
Anion
Negative ion
Cation
Positive ion
Groups most likely to become ion and why
1, 2, 6, 7
They are closer to getting a fuller outer shell than other groups
