The process of ionic bonding is not the same as the process of metallic bonding. Which of the following statements is true
about these processes?

1. In ionic bonding, only ions of the same element combine to form a compound.
2. In metallic bonding, valence electrons can move freely between atoms.
3. Substances formed through ionic bonding are not considered compounds.
4. In metallic bonding, electrons are transferred between elements in fixed ratios.