Question

question 1. which list of elements contains a metal, a metalloid, and a nonmetal? potassium (k), sodium (na), and chlorine (cl). magnesium (mg), bromine (br), and helium (he). sodium (na), boron (b), and oxygen (o). nitrogen (n), carbon (c), and phosphorus (p).

Explanation:

Step1: Recall element types

Metals are on the left - side and bottom of the periodic table, metalloids are along the staircase - like diagonal, and nonmetals are on the right - side.

Step2: Analyze each option

• Option 1: Potassium (K) and sodium (Na) are metals, chlorine (Cl) is a nonmetal. No metalloid.
• Option 2: Magnesium (Mg) is a metal, bromine (Br) and helium (He) are nonmetals. No metalloid.
• Option 3: Sodium (Na) is a metal, boron (B) is a metalloid, oxygen (O) is a nonmetal.
• Option 4: Nitrogen (N), carbon (C), and phosphorus (P) are nonmetals. No metal or metalloid.

Answer:

Sodium (Na), boron (B), and oxygen (O).