Elements in the same group on the periodic table have the same number of valence electrons. The "groups" are the column (or rows). groups are vertically and periods are horizontally.
Answer:
Stars which never disappear below the horizon are called <u>circumpolar</u> stars.
The two molecules will only react if they have enough energy. By heating the mixture, you are raising the energy levels of the molecules involved in the reaction. Increasing temperature also means the molecules are moving around faster and will therefore "bump" into each other more often.
I'd say it's partially dissociating into products
