Leonie says: "substance 2 and 4 have similar melting points, so they probably have a similar structure"

The third choice .. (:

2.00 is the !

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

Ithink the answer is d