aluminum hydroxide Al(OH)3why cant it be AlOH????tybtw what are some tips or rules when naming compoundsand hw do i identify when an element is metal or nonmetal caz i aint allowed to use a periodic table thanks
Hi there, Al is Aluminium and Aluminium has a valency (or charge) of +3This charge basically represents the number of electrons in its outer shellSo, it has three electrons it is willing to donate to become a full outer shellNote: Aluminium is a metal as most group 1, 2, 3 elements are metallicOH- is a hydroxide ion which has a valency of 1- When ionically bonded with aluminium, it requires three OH atoms(sorry would be better if i could draw a diagram to explain this S) Basically since OH atoms accepts 1 e- , and Al donates 3 e- , there needs to be 3 OH atoms to account for the three donated e- AlOH is not possible as Al has a valency of 3+ (Note: valency of atoms can change as you will notice later on when you hit redox.they will be known as oxidation numbers and can occur differently in different compounds.but lets leave it here so that you are not confused) Basically groups 1 , 2 ,3 are metallic elementsRemember the trend that as you go across the periodic table from left to right the metallicity of elements decreaseCareful there are semi-metals on the right hand-side of the table such as Tin (Sn) and Lead (Pb)There should be a dark diagonal line to distinguish semi-metals from non-metalsTransition metals are in block d Metals have valency +1 +2 and +3 (just look out for these and you will be fine) There are usually present as cations as they need to donate electronsSo in the process of naming compounds the metal is identified first and then the anion EgCaCl2 Calcium Chloride NaF Sodium Flouride CaC03 Calcium Carbonate Hope this helps D
