| What is ionisation energy? | min amount of energy needed to remove an electron from 1 mole of gaseous atoms under standard conditions
M(g) = M+(g) + e- |
| What is the energy of a photon's formula? | E = hv
v= light frequency (Hz)
h = plancks constant (6.63*10^-34) |
| What is the wavelengths formula? | c = V *wavelength
c = speed of light (3*10^8)
wavelength (m)
multiply answer by Avogadro's constant (6.02 *10^23)
/1000 = kJ mol-1 |
| Why is the 2nd ionisation energy always higher than the first? | 1) once the electron is removed = positive ion = attracts an electron more strongly than a neutral atom = more energy needed to remove the 2nd electron
2) less repulsion among the remaining electrons = pulled closer by nucleus = more strongly attracted = more difficult to remove |
| When do the large differences in IE happen? | bw energy levels |
| Why is the first IE lowest? | furthest from nucleus and shielded with the other electrons in the atom |
| What is the general trend for IE ? | increases from left to right across a period
decreases down a group |
| Why is boron an exception to the IE trend? | boron has more protons than beryllium but the IE is lower bec the electron removed from Boron is in a 2p level but for Be it is removed from the 2s level.
B's electron is farther away from the nucleus , less energy is needed |
| Why is oxygen an exception to the IE trend? | Oxygen has 2 electrons paired up in teh same p orbital but nitrogen doesnt
an electron in the same p orbital is easier to remove bec of the repulsion from the other electron |
| What does the convergence limit at higher frequency correspond to? | first ionization energy |
| What does the IE trend across periods show? | shows the existence of main energy levels and sub-levels in atoms |
| How can the electron configuration be deduced from an IE graph? | large jumps in the graph occur bw the main energy levels |
