Periodicity

Repeating pattern of properties shown across different periods within their position in the periodic table

Alkalis, less dense than water, fizzing, floats, dissolve

Same number of outer shell electrons, same electron configuration

Reactivity increases as you go down the group due to more shells, easier to lose electrons, weaker attraction to nucleus, less atomic radius

Energy required to remove one electron from each atom in a mole of gaseous atoms Endothermic

Na (g) > Na+ (g) + e- Na+ (g) > Na2+ (g) + e- Na2+ (g) > Na+ (g) + e-

O (g) > O+ (g) + e- Atoms are singular so not O2

Measure of energy required to remove each electron in turn

Electrons in outer shell = lowest group of crosses Period number = number of groups

Big jump between ionisation energies

Atomic radius Electron shielding Nuclear charge

Distance from nucleus to outer electron shell

Amount of shells Shells lessen electron repulsion

Charge of nucleus (protons in nucleus)

Decreases

Increases

Number of shells increases Shielding increases Atomic radius increases

Number of protons increases Increased nuclear attraction Atomic radius decreases Similar shielding

Atomic radius Nuclear charge Electron shielding

Bosons outer electron is in a 2p orbital rather than a 2s 2p electron is slightly more distant from the nucleus than the 2s Also, it is partially shielded by the 2s electrons as well as the inner electrons Both of these factors offset the effect of the extra proton

Despite the extra proton in the oxygen nucleus Shielding is identical in nitrogen and oxygen and the electron is being removed from an identical orbital Difference is that in oxygen, the electron being removed is one of the 3px2 pair Repulsion between the 2 electrons in the same orbital means that the electron is easier to remove than it would otherwise be

3BP 1LP Layers slide easily due to weak forces between layers Lots of strong covalent bonds so high MP Delocalised electrons between layers allow graphite to conduct electricity Layers far apart so low density Insoluble as covalent bonds too strong strong to break

Tetrahedral Conduct well due to tightly packed rigid arrangement V high MP due to many strong covalent bonds, v hard Doesn’t conduct electricity due to no delocalised electrons Insoluble as covalent bonds too strong

Same as diamond