How do u do number two with mole ratios

☆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

The answer would be true

Ithink about 50 % of an original isotope's number of atoms remain

Answerchemical energy;