5)
the element sodium has an atomic number of 11 and a mass number of 23. how many protons, neutrons, and
electrons does one atom contain?

Atoms must have equal numbers of protons and electrons. In our example, an atom of krypton must contain 36 electrons since it contains 36 protons. Electrons are arranged around atoms in a special way.

Explanation:

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).