Question

Which statement about the elements in the periodic table is true

Answer 1

A. The number of valence electrons increases as atomic mass increases. == Generally true for the representative elements since atomic mass generally increases with increasing Z.

B. The reactivity of alkali metals increases as atomic mass increases. == True. Atomic mass increases down the column and so does reactivity

C. The reactivity of the halogens increases as atomic mass increases. == False. Reactivity decreases down the column.

D. The number of valence electrons decreases across a period. == False. In general, the number of valence electrons increases across a period, particularly for the representative elements.

Answer 2

The reactivity of alkali metals increases as atomic mass increases.

Step-by-step explanation:

There are six elements in the periodic table that can be classified as alkali metals. These elements are extremely reactive and it is correct to say that the reactivity of alkali metals increases as the atomic mass increases.

These metals can be found in the IA family of the periodic table and contain the names: Lithium, Sodium, Potassium, Rubidium, Cesium, Francium.