Question

1. choose the best answer.

for metals, how does reactivity trend in the period?
it decreases across (left to right) a period.
it increases across (left to right) a period.

1. choose the best answer.

for nonmetals, how does chemical reactivity trend in a period?
it decreases across (left to right) a period.
it increases across (left to right) a period.

1. use a periodic table to choose the best answer.

which element is more chemically reactive?
sr
rb

Explanation:

• For metals, as we move from left to right across a period, the atomic size decreases, and the attraction between the nucleus and the outermost electrons increases. So, it becomes more difficult for metals to lose electrons (which is how they react), and reactivity decreases.
• For non - metals, as we move from left to right across a period, the atomic size decreases, and the attraction for electrons (to complete their octet, which is how non - metals react) increases. So, reactivity increases.
• Rubidium (Rb) is in Group 1 (alkali metals) and Strontium (Sr) is in Group 2 (alkaline earth metals). Alkali metals are more reactive than alkaline earth metals because they have one valence electron which is easier to lose compared to the two valence electrons of alkaline earth metals.

Answer:

1. It decreases across (left to right) a period.
2. It increases across (left to right) a period.
3. Rb