Potassium (k) and copper (cu) are both in period 4. they both have
a) similiar properties
b)the same number of protons
c)four electron shells
d)the same number of electrons

The answer is C.

Explanation:hope this helps you!

quartz

explanation:

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.