$2.3B to buy snack-maker includes debt.
New concerns about Britain's decision to leave the European Union.
Company sought Chapter 11 bankruptcy protection in July, 2012.
Market ends week up 3 percent, its biggest gain since November.
Traders show they feel less anxious about Brexit vote last week.
Mondelez International offered nearly $23 billion in cash and stock.
U.S. stocks echo strong gains in global markets
Data on economy, housing market puts traders in buying mood.
“Brexit” vote could bring long-term financial fallout for some companies.