## Q. 4.3

Zinc, a micromineral, is needed for metabolic reactions in cells, DNA synthesis, the growth of bone, teeth, and connective tissue, and the proper functioning of the immune system. For an atom of zinc that has a mass number of 68, determine the number of:
a.  protons                                b.  neutrons                               c.  electrons

## Verified Solution

a.  Zinc (Zn), with an atomic number of 30, has 30 protons.
b.  The number of neutrons in this atom is found by subtracting the number of protons (atomic number) from the mass number.
Mass number        –        atomic number       =        number of neutrons
$\space$      68                      –                   30                     =                       38
c.  Because a zinc atom is neutral, the number of electrons is equal to the number of protons.
A zinc atom has 30 electrons.

 ANALYZE THE PROBLEM Given Need Connect zinc (Zn), mass number 68 number of protons, neutrons, electrons periodic table, atomic number