ionisation energy Flashcards
what does it mean for an electron to be ionised ?
being removed from an atom or molecule
what is energy needed to remove the first electron called?
first ionisation energy
what is the equation for first ionisation energy?
1 mol of gaseous element -> 1 mole of gaseous equation 1+ ions + 1 mole of electrons
what state symbol is used for ionisation energy ?
(g)
the lower the ionisation energy …
the easier it is to form a positive ion
what type of process is ionisation ? explain
endothermic , you have to put in energy to remove an electron from an atom or molecule .
what does a high ionisation energy mean when trying to remove an electron ?
theirs a high attraction between the electron and the nucleus so more energy is needed to remove an electron
what are the three factors affecting ionisation energy ?
nuclear charge
distance from the nucleus
shielding
why does nuclear charge affect ionisation energy ?
the more protons in the nucleus ,the more positvley charged the nucleus is and the stronger the attraction for the electrons
why does distance from the nucleus affect ionisation energy ?
attraction falls rapidly with distance ,an electron close to the nucleus will be much more strongly attracted than one farther away .
Why does shielding affect ionisation energy ?
the number of electron between the nucleus and outer electron increases .
the electrons feel less attraction to the nucleus .
what is the second ionisation energy ?
the energy needed to remove an electron from each ion in one mole of gaseous 1+ ions
what is the equation for 2nd ionisation energy?
o+(g)->O2++e-
which is higher ,first or second ionisation energies ? explain why
second as the electron is being removed from a positive ,ion which will take more energy
what factor determines how high the second ionisation energy is ?
electron configuration
what is third ionisation energy ?
the energy needed to remove an electron from each ion in 1 mole of 2+ ion
is third ionisation energy greater than second ionisation energy ?
yes , more protons means there is more attraction between electrons to nucleus
can you leave the nucleus of the atom and nothing else ?
yes ,by removing all the electrons
what is successive ionisation energy ?
the ionisation energy after each electron
what is the general eqaution for nth ionisation energy?
X^(n-1)(g) -> X^n+(g) + e-
what is the trend for first ionisation energy in group two?
decreases as you go down
what does the trend in group two for first ionisation energy provide evidence for ?
the existence of electron shells because as each element going down group two has one more electron shell than the last, the extra shell will shield the electron from the nucleus also it will be further from the nucleus which decreases the electrons attraction to the nucleus
what happens with ionisation energy as you move across a period ?
ionisation energy increases and it gets harder to remove an electron
why does the trend across periods with ionisation energy happen ?
the number of protons increasing ,which means a stronger nuclear attraction
what happens with electron energy across a period ?
stays roughly the same level .even if the orbitals are different types.this means there’s generally little extra shielding effect or extra distance to lessen the attraction from nucleus
what happens with ionisation energy between group 2 and 3 ?
a small drop in ionisation energy level ,which shows the sub shell structure
what happens between group 5 and 6 in ionisation energy ?
a small drop due to electron repulsion between orbitals
what does a graph of successive ionisation energies provide evidence for?
the shell structure of atoms
what happens within each shell with successive ionisation energy and why ?
increases because electrons are being removed from an increasingly positive ion so there’s less repulsion amongst the remaining electrons and their held more strongly by the nucleus .
what does a big jump in ionisation energy mean ?
when a new shell is broken into as a electron is being removed from a shell closer to the nucleus
how do you find which group of a periodic table an element belongs to from a ionisation energy graph ?
count how many electrons are being removed before the first big jump to find the group number
how can these graphs predict electronic structure ?
count how many point there are between each big jump to find how many electrons are in each shell
