First page: iii) Potassium is located in Group 1, Period 4
iv) 1s²2s²2p^6 3s²3p³
2. a. i) Mg, A
ii) Sulfur (S)
iii) Electron configuration: 1s² 2s² 2p^6 3s² 3p² Name: Silicon
b. i) Element A would be more reactive with water because A has more shells than magnesium. This is because A is located under Mg, meaning it has more elctorns and shells. Because A has more shells, it is more likely to lose electrons than Mg, making it more reactive. Also, the general trend for reactivity is that elements are more reactive as you move down a group.
ii) Single replacement - Mg + H₂O ⇒ MgO + H₂ (I'm not completely sure)
I don't know how to do the rest. Hope this helps!
