Calculate the number of atoms of copper represented by 127.08 g of copper.

The molar mass of copper is 63.55 g/mol. So, you convert grams to moles 127.08/63.55 =1.999 moles copper. Now, 1 mole = 6.022e23 atoms, so multiply # of moles by 6.022e23. 1.999 x 6.022e23= # of atoms of copper.

And a) oxygen i believe

☆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