help with chemistry ???

Question

1) A beaker contains a sample of 0.5 mole of potassium bromide ,KBr.
a)Find the number of formula units of KBr in the beaker.
b)Calculate the total number of ions present in the beaker.

2)How many chloride ions in 0.5 moles of magnesium chloride, MgCl2

Answer 1

1a. Dont know exactly what a formula unit is.
b. Since both K and Br and expeced to be in ions (K+ and Br-), we have 1 "mole" of ions or 6.02x10^23 ions.

2. Since each molecule of MgCl2 provides 2 Cl- ions, 0.5 moles will provide 1 "mole" of Cl- ions. Same number as in 1b.