Please help 1: what is a limitation of using marbles as models for atoms?

2: density is the mass of matter in a given volume. materials that are less dense flood on denser materials. explain why ice floats on water.

3: how dose the overall charge of oxygen-16 compare to oxygen-17 and oxygen-18?

4: how dose an elements atomic mass differ from its mass number?

In november 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. the chunk of ice was estimated to be 98 mi long, 25 mi wide, and 750 ft thick. a typical backyard swimming pool contains about 24,000 gallons of water. how many of these pools could you fill from the water in this iceberg? (assume the iceberg is a rectangular solid of the above dimensions and consists of water only). express answer in scientific notation.