Which of the following elements is a metalloid?

Statement $I :$ Acid strength increases in the order given as $HF < HCl < HBr < HI$.
Statement $II :$ As the size of the elements $F, Cl, Br, I$ increases down the group,the bond strength of $HF, HCl, HBr$ and $HI$ decreases and so the acid strength increases.
In the light of the above statements,choose the correct answer from the options given below.

What is an amphoteric oxide?

Considering the elements $B$,$Al$,$Mg$,and $K$,the correct order of their metallic character is:
$(a)$ $B > Al > Mg > K$
$(b)$ $Al > Mg > B > K$
$(c)$ $Mg > Al > K > B$
$(d)$ $K > Mg > Al > B$

The number of metalloids in the following elements are $Si$,$Mn$,$B$,$F$,$Cu$,$Ag$,$K$,$Sb$,$As$,$Na$,$Ge$.

What are the major differences between metals and non-metals?