Atomic Structure Flashcards
State the masses of the 3 subatomic particles
Electron- 1/1840 proton-1 neutron-1
What’s the mass of an electron
1/1840
What’re the charges of the subatomic particles
Electron - -1 proton-+1 neutron- 0
What’s the radius of an atom
10^-10m
What’s the radius of the nucleus
10^-14
What’re nucleons
Particles inside the nucleus (protons and neutrons)
What’s stronger electrostatic or nuclear forces
Electrostatic since its what holds electrons together
Name the scientist who discovered the atom
Dalton
What were daltons findings
-all elements are composed of atoms
-1 atom can’t be changed to another (false)
- atoms can’t be subdivided,created or destroyed
- atoms of different elements combine to form chemical compounds
Who discovered the electron
Jj Thompson
Who discovered that the nucleus was positively charged and dense, and was mainly empty space
Rutherford
Who discovered electron shells
Niels Bohr
What’s the quantum mechanical model
States that electrons aren’t in fixed places but move continually in clouds
Place energy levels ,orbitals and sub shells in order
Energy levels->subshells-> orbitals
What’re the 4 subshells
S,p,d,f
What do A E and Z stand for in the periodic table
A- atomic mass number
E- element symbol
Z- atomic number
Define relative atomic mass
Mean mass of an atom compared to 1/12th of a carbon 12 atom
Define an ion,cation and anion
Ion- a charged particle
Cation- positively charged particle
Anion-negatively charged particle
How do you calculate RAM
Mass x abundance of each isotope /100
Why is the TOF mass spectrometer kept in a vacuum
To prevent ion producted to collide with molecules in the air
What happens in ionization stage during mass spectroscopy
Sample dissolved in polar volatile solvent and is either sprayed with electrons or gains H+ from the solvent.
Solution pumped through needle and converted into fine mist,high voltage applied and sample disperses in an aerosol and then evaporates again.
What happens during acceleration in mass spectroscopy
Ions accelerated by electric field so they all have the same kinetic energy.
What happens during ion drift in mass spectroscopy
Ions enter a region without an electric field so they drift through it,lighter ions drift faster than heavier ions
What happens during detection in mass spectroscopy
Lighter ions each detector in less time and gain an electron which causes a current to flow,size of current is proportional to abundance of the isotope.
What’s on the x and y axis of the mass spectra
X- relative abundance in percent
Y- mass to charge ratio (m/z)
Name the 6 stages of mass spectrometry
Injection,heated,ionized,ion drift,detection
Why was carbon picked as the baseline rather than hydrogen
It’s not flammable and is the closest to a whole number
What’re the 2 hydrogen isotopes
Deuterium (2h)
Titrium (3h)
How is velocity calculated in terms of time of flight
V=d/t
How is kinetic energy calculated
KE=1/2mv^2
Define an orbital
Region of space where there’s a high probability of finding an electron
State the equation for calculating the number of electrons in a shell number
2n^2
How much electrons can an orbital hold
2
What’s another name for the shell number
Principal quantum number
State the number of orbitals within each subshell
S- 2
P- 3
D- 5
F- 7
State the number of electrons each subshell can hold
S-2
P- 6
D- 10
F- 14
What’s the shape of the s subshell and in what period is it located
Spherical shape,in all periods
What’s the shape of the p subshell and in what period is it located
Dumbell shaped,in all periods but the first
What’s the shape of the d subshell and in what period is it located
Various shapes, in energy energy level but first and second
Why are the subshells placed in different groups on the periodic table table
The elements in those blocks have the valence electrons in that subshell. Ex- s block has its valence electrons in the s subshell
What comes first,3d or 4s
4s always filled before 3d
What’s hunds rule of multiplicity
Electrons singly occupy orbitals first before doubling up when in opposite spins
What’s afbaus principal
Electrons enter the shell closest to the nucleus first
What’s paulis exclusion principal
Electrons in orbitals always have opposite spins to minimize repulsion between electrons
What 2 elements have 2 half filled shells rather than 1 to increase stability (4s removed first even though 3d is last)
Copper and chromium
Define ionisation energy
The energy required to remove 1 mole of electron to from 1 mole of gaseous atom to form 1 mole of 1+ ion
Define 4th ionisation energy
The energy required to remove 1 mole of electron from 1 mole of gaseous 3+ ions to form 1 mole of 4+ gaseous ions
Write the ionisation equation for Mg5+
Mg5+(g)-> Mg6+(g) + e-
What’re the 3 factors than affect ionisation energy
1- distance between nucleus and outermost electron (atomic radius)
2-charge on nucleus
3- shielding
How does ionisation energy change as you go down a group and why
Decrease due to higher atomic radius which decreases the attraction between electrons and nucleus
How does ionisation energy change as you go across a period and why
Increase due to increasing amount of protons which makes it harder to remove an electron
What’re the 2 reasons for any ionisation energy exceptions
1- opposite spins repel electrons
2- enters new subshell
