Answer
Classifying each element in the fourth row/Period 4 of the periodic table as a metal, nonmetal, or metalloid:
Metals in period 4:
Potassium(K), Calcium (Ca), Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn) and Gallium (Ga).
Nonmetals in period 4:
Selenium (Se), Bromine (Br), Krypton (Kr)
Metalloids in period 4:
Germanium (Ge), Arsenic (As)
