Atomic structure Flashcards
Define Atomic Number
Equal to the number of protons
Define mass number
Equal to the number of protons and neutrons combined
define isotopes
Same number of protons, different number of neutrons
why do isotopes have the same chemical property
They have the same electron configuration
What did Rutherford’s model prove
Atom mostly made up of empty space, most passed through. Alpha particles have positive charge. Atom should have a small positive nucleus
What did the Bohr model state
A small positive nucleus with electrons surrounded in shells. Neutrons in the nucleus
Define Ionisation energy
The amount of energy required to remove one mole of electrons from a mole of atoms in a gas state. * always include the state symbol (g)
Factors that influence IE
- Nuclear charge, number of protons- more protons, stronger attraction to nucleus, requires more energy
- Distance from the nucleus- Electron closer to nucleus, stronger attraction, more energy required.
- Shielding- Electron on shell further from the nucleus- more shielding, weaker attraction. Less energy to remove.
Trend in IE across the group: why is second IE high then first? include deviations
Why- the attraction between the electron and protons becomes stronger as there a less electrons being attracted by the same number of protons.- 2nd electron is removed from an ion that already has a positive charge
Trends: general increase, same shielding, more protons.
Deviations P2: Electron to be removed from Be is from a 2s sub-shell, from B it is in a 2p sub-shell. 2p is higher, less energy required to remove.
Electron to be removed from N is unpaired, O is paired. Electron pairs repel, requires less energy to remove.
P3: electron to be removed from Mg is 3s, Al is 3p. 3p= higher sub-shell, requires less energy to remove.
Electron to be removed from P is unpaired, S is paired. Electron pairs repel, Sulfur has lower IE due to less energy being required to move
Change in atom size
factors affecting- same shielding, more protons so greater nuclear attraction on outer electrons- smaller ion
more shielding, further from the nucleus, weaker nuclear attraction, more shielding.
Electron configuration
Cr: 1s2 2s2 2p6 3s2 3p6 4s2 3d9
Cu: 1s2 2s2 2p6 3s2 3p6 4s1 3d10
trends in IE down the group, atomic size trend across the period
Atomic radius increases, the number of shells increases so amount of shielding increases.
Atomic radius gets smaller, nuclear charge increases, greater attraction between electrons and nucleus, shielding remains the same.
TOF spectrum
Vacuum to prevent particles colliding with air.
acceleration: positive ions attracted to a negatively charged plate and accelerate towards it. Once accelerated all have the same KE.
Ion Drift- particles separate based on their masses.
Detection: generates a current once hits the detector- generating a current proportional to the number type of each ion.
Why are the sample particles ionised?
So they can be accelerated towards the negatively charged pate and generate a current once hit the detector
How is the ion accelerated? and how are they separated? How are they detected?
Positive ions are attracted to negatively charged plate, all have the same kinetic energy.
Ions travelling at higher speeds reach the detector first.
detection: Each ion hits the detector, gains an electron, generated a current which is proportional to abundance of ion.
