How many lone pairs are around the central atom in the Lewis formula for the
hydrogen sulfate ion, HSO4-?

The answer to your question is None, sulfur share of its electrons

Explanation:

Just remember:

Sulfur, S, has 6 electrons in its outermost shell

Hydrogen, H, has 1 electron in its outermost shell

Oxygen, O, has 6 electrons in its outermost shell

See the picture below

The electrons of sulfur are in blue

The electrons of oxygen are in red

The electron in hydrogen is in yellow

Sulfur is the central atom and it shares all its electrons with the oxygen.

a) the particles of the chair are strongly held together.