Can compounds be broken down into the elements they are made of?

yes, some can

Explanation:

because like salt an other compounds by being decomposed

no

explanation:

go away, people want answers, not to hook up

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.