Which of the following statements describes how the periodic table is organized?

1. The elements are organized alphabetically.

2. The elements are organized by their size.

3. The elements are organized by the date they were discovered.

4. The elements are organized by their properties.

4.The elements are organized by their properties.

Explanation:

neutrons are in the middle of the atom and the electrons, which are much smaller.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).