Which metal is protected by a layer of its own oxide?

What is the difference between the first member of a group and the other elements in the $s$- and $p$-block? Why?

What is the formula for meta-boric acid?

Borax is actually made of two tetrahedra and two triangular units joined together and should be written as: $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$. Consider the following statements about borax:
$a.$ Each boron atom has four $B-O$ bonds
$b.$ Each boron atom has three $B-O$ bonds
$c.$ Two boron atoms have four $B-O$ bonds while other two have three $B-O$ bonds
$d.$ Each boron atom has one $-OH$ group
Select correct statement$(s)$:

The dissolution of $Al(OH)_3$ by a solution of $NaOH$ results in the formation of

Choose the incorrect statement/reaction.