ATOMIC STRUCTURE/AOS Flashcards
What was Niels Bohr’s model & discovery?
Model: where electrons exist in shells or orbits of fixed energy
Discovered: When electrons move between shells, electromagnetic radiation (with fixed energy or frequency) is emitted/absorbed
protons charge and mass
mass: 1
charge: +1
Neutrons charge and mass
mass: 1
Charge: 0
Electrons charge and mass
charge: -1
Mass: 1/1840
Iosotopes
same No of protons
Different No of neutrons
same e- configuration
1st ionisation energy
ENTHALPY CHANGE WHEN ONE MOLE OF e- IS REMOVED FROM ONE MOLE OF GASEOUS ATOMS TO FORM ONE MOLE OF GASEOUS 1+ IONS
trend in ionisation energy along a period?
ionisation energy increases
why does ionisation energy increases along a period?
atomic radius decreases
increases in charge
outer e- is strongly attracted to nucleus so requires so more energy required to remove outer e-
trend in ionisation energy down a period?
ionisation energy decreases
why does ionisation energy decreases down a period?
attraction between nucleus and outer e- decreases
more shielding
less energy required to remove outer e-
Trend in ionisation energy across P2? (6 marker)
STAGE 1
General increase in IE
same shielding as same number of shells
greater attraction between nucleus and outer e-
STAGE 2
B lower than Be
outer e- in 2P
higher in energy than 2S
STAGE 3
O lower than N
2 e- in 2P needed to be pair
e- pair repulsion
Define Ar
Mean mass of an atom of an element /one twelfth of the mean mass of an atom of the carbon 12
Define Mr
mean mass of a molecule of a compound/ 1 twelfth of the mean mass of ab atom of the carbon 12
Calculate:
No of particles
moles x 6.022x10^23
calculate moles
(2 equations)
Mass/ Mr
Con x Vol