At the start of period 7, from francium to thorium, the melting points of the elements increase (as in other periods), because the number of delocalised electrons each atom contributes increases from one in francium to four in thorium, leading to greater attraction between these electrons and the metal ions as their charge increases from one to four.
Έχοντας θέση στην αρχή της περιόδου 7, η οποία εκτείνεται από το φράγκιο μέχρι το θόριο, α σημεία τήξης των στοιχείων αυξάνονται (όπως σε άλλες περιόδους), επειδή ο number of delocalised electrons each atom contributes increases from one in francium to four in thorium, leading to greater attraction between these electrons and the metal ions as their charge increases from one to four.