Which of these equations is balanced?
What is this element?
What is the atomic number of this element?
How many protons are there in the nucleus of this element?
How many electrons are there around the nucleus of this element?
Which group number are the halogens?
Which group number are the alkali metals?
Which group number are the noble gases?
How many electrons can the 1st shell hold?
How many electrons can the 2nd shell hold?
How many electrons do the alkali metals have in their outer shell?
How many electrons do the halogens have in their outer shell?