Atomic radii decrease as you move from left to right across a period, because the increased number of protons create more positive charge attraction for electrons which are in the same shell with similar shielding.

Atomic radii decrease as you move from left to right across a period, because the increased number of protons create more positive charge attraction for electrons which are in the same shell with similar shielding.

Period 2 = Li, Be, B, C, N, O, F, Ne

There is a general trend across is to increase. This is due to increasing number of protons as the electrons are being added to the same shell

Mg has its outer electrons in the 3s sub shell, whereas Al is starting to fill the 3p subshell. Al’s electron is slightly easier to remove because the 3p electrons are higher in energy.

Sulphur’s outer electron is being paired up with an another electron in the same 3p orbital. When the second electron is added to an orbital there is a slight repulsion between the two negatively charged electrons which makes the second electron easier to remove.

For Na, Mg, Al- Metallic bonding : strong bonding – gets stronger the more electrons there are in the outer shell that are released to the sea of electrons. A smaller positive centre also makes the bonding stronger. Higher energy is needed to break bonds.

Si is Macromolecular: many strong covalent bonds between atoms, high energy needed to break covalent bonds– very high mp +bp

(S)- simple Molecular : weak van der waals between molecules, so little energy is needed to break them – low mp+ bp

it has more electrons (S8 =128)(P4=60) so has stronger v der w between molecules