Question

javiers teacher gives him four cards, each displaying information about an element, and asks him to put them in order of reactivity. the elements are carbon (c), helium (he), magnesium (mg), and potassium (k). javier arranges the elements in order from most reactive to least reactive, as shown in the diagram. is javiers arrangement correct? why or why not? a. yes, because the reactivity of elements decreases as their atomic numbers decrease. b. yes, because the reactivity of elements decreases from left to right on the periodic table. c. no, because the reactivity of elements decreases from right to left on the periodic table. d. no, because the reactivity of elements decreases as their atomic masses increase.

Explanation:

Reactivity of metals generally decreases from left - to - right across a period and increases down a group in the periodic table. Potassium (K) is an alkali metal, magnesium (Mg) is an alkaline - earth metal, carbon (C) is a non - metal, and helium (He) is a noble gas. Noble gases are the least reactive elements. Among metals, alkali metals are more reactive than alkaline - earth metals. So, the order from most reactive to least reactive is correct as K > Mg > C > He. The reactivity of elements decreases from left to right on the periodic table for main - group elements.

Answer:

B. Yes, because the reactivity of elements decreases from left to right on the periodic table.