Chemistry Relative Sizes of Atoms and Ions?

Chemistry Relative Sizes of Atoms and Ions?
Hi guys...im Frank,thank god my friend told me about this site,u people are my only hope now.
Here is a question from my chem homework
I am trying to rank the size of atoms and ions for the following elements:
Be[2+]
F[-]
Li[+]
Cl[-]
H[-]
I tried to compare their atomic radius,but I kept getting it wrong!(I am not sure about the radius for H-)
These are the wrong answers I got wrong
Cl->F->Li+>Be2+>H- (wrong)
H->Cl->F->Li+>Be2+ (wrong)
Cl->H->F->Li+>Be2+ (wrong)
Plz let me know the correct order,and of course,the process
thanks!

I'm a little surprised that you're using Baidu (a Mandarin site) for a question in English,but here goes:
When an atom loses an electron to become a cation (e.g.Be -> Be2+,Li -> Li+),the atomic radius,AKA size,decreases - this makes sense because now the proton:electron ratio has increased so the 'pull' on each electron is stronger.The reverse applies for atom -> anion (F -> F-) as there are now more electrons than protons so the attraction each electron experiences is weaker,thus they are able to spread out further.Does this make sense?
Now we look at the periodic table.
H is in period 1
Li,Be and F are in period 2
Cl is in period 3
The larger the period,the more 'shielding' occurs - so all else being equal the atom in the larger period # must be larger as the outermost electrons experience less attraction.
So the largest is Cl-,because it is (1) an anion and (2) in the largest period.
Among Li+,Be2+ and F-,F- is an anion - so it is the largest.
Then we have Li+,Be2+ and H-.All these have only 2 electrons,which to say shielding is the same (2 electrons = 1 electron shell).So we compare the # of protons:
Li = 3 protons
Be = 4 protons
H = 1 proton
So with regards to size,H- > Li+ > Be2+
And therefore,Cl- > F- > H- > Li+ > Be2+.This is in DESCENDING order.Make sure you fill it in correctly for descending v.ascending.