Changes

A [[Period]] '''period''' is a row on the [[Periodic Table]] whose [[element]]s all have the same number of [[Electron Shell]]s.

: [[Atomic Number]] increases as you move along a '''period'''. {| class="wikitable"|-|[[File:PeriodicTablePeriods.png|center|600px]]|} ====Trends within Periods====: The [[Chemical Property|chemical]] and [[Physical Property|physical properties]] of [[element]]s change as you move along a [[Period (Chemistry)|period]].{| class="wikitable"| style="height:20px; width:300px; text-align:center;" |'''Period 2 Melting Points'''| style="height:20px; width:300px; text-align:center;" |'''Period 3 Melting Points'''|-|[[File:Period2MeltingPoints.png|center|300px]]|[[File:Period3MeltingPoints.png|center|300px]]|-| style="height:20px; width:300px; text-align:center;" |There is a trend in the [[Melting Point]]s as you move along the [[Period (Chemistry)|period]].| style="height:20px; width:300px; text-align:center;" |A similar trend can be seen in the next [[Period (Chemistry)|period]].|} ==Key Stage 4=====Meaning===A '''period''' is a row on the [[Periodic Table]] whose [[element]]s all have the same number of [[Electron Shell]]s. ===About Periods===: [[Atomic Number]] increases as you move along a '''period'''.: The number of the '''period''' is the same as the number of [[Electron Shell|electron shells]]. ====Trends within Periods===={| class="wikitable"|-|[[File:Period2ElectronShells.png|center|600px]]|-|[[File:Period2ElectronShielding.png|center|600px]]|-| style="height:20px; width:600px; text-align:left;" |For the first 3 [[element]]s [[Lithium]], [[Beryllium]] and [[Boron]] all lose [[electron]]s in [[Chemical Reaction|chemical reactions]]. The [[reactivity]] decreases as you go across the [[Period (Chemistry)|period]] because:*The outer [[electron]]s are all roughly the same distance away from the [[Atomic Nucleus|nucleus]].*The [[Electrical Charge|charge]] on the [[Atomic Nucleus|atomic nucleus]] increases as you move go across the [[period]]but the [[electron]] shielding caused by the two inner [[electron]]s remains the same. This causes the [[electron]]s to experience a greater [[force]] of [[attraction]] as you move along the [[period]], making it harder for the [[atom]]s to lose [[electron]]s and become [[ion]]s. [[Nitrogen]], [[Oxygen]] and [[Fluorine]] can all gain [[electron]]s to become [[Negative Charge|negative]] [[ion]]s in certain [[Chemical Reaction|reaction]]s. The [[reactivity]] increases as you go across the [[Period (Chemistry)|period]] because:*The outer [[electron]]s are all roughly the same distance away from the [[Atomic Nucleus|nucleus]].*The [[Electrical Charge|charge]] on the [[Atomic Nucleus|atomic nucleus]] increases as you move go across the [[period]] but the [[electron]] shielding caused by the two inner [[electron]]s remains the same. This causes the [[electron]]s to experience a greater [[force]] of [[attraction]] as you move along the [[period]], making it easier for an [[atom]]s to gain more [[electron]]s to become [[ion]]s.|}