periodicity Flashcards
what are elements in the periodic table ordered by?
elements are ordered by proton number NOT MASS NUMBER
ELEMENTS IN THE SAME PERIOD HAVE THE SAME …
NUMBER OF ELECTRON SHELLS
S, D, P AND F BLOCKS IN PERIODIC TABLE.
https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/ESG8zd9OycVMpypGvASQpWkBJjd9kjqrBrQH9v6RVaav2A?e=xrPNK9
as we go across period 3, the atomic radius ….
decreases
as we go across the period why does the nuclear charge increase? and what effect does this have on the outer electrons
because the number of protons increases. this pulls the outer shell of electrons further in towards the nucleus.
as we go across the period what effect stays the same
same shielding effect (shielding - protection of inner electron shells from the nucleus)
explain the trend of atomic radius down the group.
increases down the group due to extra electron shells added for each element down the group.
explain the trend of melting point from metals Na to AL in period 3.
https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/ESk_54TIBN1BtX-mheqkU7MB8qJhllXgprmjH9PaW5d9IA?e=Y1trVY
which element across period 3 has the highest melting point and why?
Silicon as it has a giant covalent (macromolecular) structure. Hence it has many, strong covalent bonds which hold the silicon atoms together. a large amount of energy is needed to overcome these strong covalent bonds as a result.
why does phosphorus (p4) have a lower melting point than silicon?
due to a weaker simpler molecular structure, and the melting point is determined by weaker VDW forces, so phosphurs has weaker VDW’s.
why does sulfur have a higher melting point than phosphurus?
due to a larger simple molecular structure. hence it has larger VDw forces and hence a higher melting point.
why does chorine have a lower melting point than both phosphorus and sulfur?
due to a even smaller simple molecular structure. hence it has smaller vdw forces and hence a lower melting point
why does argon have a lower melting point than the rest of the elemnents in period 3?
as it only exists as indidual atoms, hence it has smaller vdw forces and hence a lower melting point.
define ionisation energy
the minimum amount of energy required to remove 1 mole of electrons from 1 mole of atoms in the gaseous state.
why is ionisation an endothermic process?
cuz it requires energy and hence have a positive value
how do affectors shielding, nuclear charge and atomic size affect the level of ease of removal of electrons from the outer shell? (i.e ionisation)
shielding:
the more electron shells between the positive nucleus and outer electron that is being removed, the less energy is required to remove it as there is a weaker attraction.
nuclear charge:
the more protons in the nucleus, the bigger the attraction between the nucleus and outer electrons. this means more energy is required to remove the electron.
atomic size:
the bigger the atom the further away the outer electron is from the nucleus, hence the attractive force between the nucleus and outer electron is weaker, making it easier to remove electrons.
shielding has a bigger impact to ionisation than….. (when going down the group)
nuclear charge (this mainly comes into play when looking across the period)
whats successive ionisation
the removal of more than 1 electron from the same atom
general trend of energy needed in successive ionisation
general increase in energy as removing an electron from an increasingly more positive ion. (electron being removed is even closer to the nucleus hence the attractive is stronger)
diagram of successive ionisation energies.
https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/ERrda91O1lFJrimtDwQNZGABQhXyNBw1nkwx86XxO5DX2Q?e=8DhyWz
explain trend of 1st ionisation energy down a group
https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/EYOTcQBLhcBJrtkQUg3Bw2UBGTz2cxHgyg7VS0VT5IHbTw?e=dEJh6z
explain the trend of 1st ionisation energy across a period.
https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/EVIvu4XqD4RMmNcXKTZisIsBnmFvsEPL9hLsJPjLjh4AAA?e=fQPsFp
there are dips in 1st ionisation energy across period 3 at aluminium, and sulfur. explain these dips.
https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/EYChMO0aoH5Khd1MVE2_3GIBYDl3s_mORqGMSLNWTKlZIg?e=HgW7in
