Which statement about the elements in the periodic table is true? a) the number of valence electrons increases as atomic mass increases. b) the reactivity of alkali metals increases as atomic mass increases. c) the number of valence electrons decreases across a period. d) the reactivity of the halogens increases as atomic mass increases.

b) The reactivity of alkali metals increases as atomic mass increases.

The answer is B) The reactivity of alkali metals increases as atomic mass increases. Just checked on Gradpoint and it was correct!

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.

increased stability in the completion of fluorine's outer shell.