Ametal atom loses electrons from its outermost energy level and acquires a (positive) or (negative) charge. these electrons join a nonmetal atom. the ionic compound formed because of this transfer of electrons is electrically (positive) or (neutral) .

acquires a positive charge

electrically (neutral)

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.