What is the element in period 3 that required requires the least amount of energy?

How is the atomic number of a nucleus changed by alpha decay

What is conserved in the reaction shown below? h2(g) + cl2 (g) --> 2hcl(g)a. mass onlyb. mass and moles onlyc. mass, moles, and molecules onlyd. mass, moles, molecules, and volume

Which property of water causes water drops to bead on a freshly waxed car?