It is a molecule because hydrogen is an element.
An element is made up of molecules
By 1.23 x 1024 you mean 10 to the power of 24 molecules? If so all you need to do is divide the number of molecules you have by Avagadros number, 6.022 x 10^23. This will give you the mols of water, or the mols of anything, since there is always 6.022 x 10^23 molecules in 1 mol of substance.
1.23x10^24 atoms/6.022x10^23 atom/mol = 2.04 mol H20
A covalent bond is formed between two non-metals that have similar electronegativities.
An <em>i</em><em>o</em><em>n</em><em>i</em><em>c</em><em> </em><em>b</em><em>o</em><em>n</em><em>d</em> is formed between a metal and a non-metal. Non-metals(-ve ion) are "stronger" than the metal(+ve ion) and can get electrons very easily from the metal. These two opposite ions attract each other and form the ionic bond.
Calcium chloride forms an ionic compound with a
regularly arranged lattice of oppositely charged ions.
The Na+ and Cl- ions are held together by
strong electrostatic forces.
Hope that helps