Sodium an alkali metal and chlorine a halogen are both in period 3? of the periodic table. which element has a higher ionization energy? explain

chlorine

Explanation:

Because in periodic table across the period from left to right, ionization energy increases due to increase in the nuclear charge as more and more electrons are added to the same shell.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

all eukaryotic cell have mitochondria : )