pure sodium and chlorine are extremely dangerous, but when combined the result in substance that we use every day. How do you think the properties of sodium and chlorine change when they are combined to make sodium chloride?

Explanation:

chlorine has 7 valence electrons while sodium has 1. on their own, they are very reactive elements. a full valence electron shell has 8 electrons, so when elements combine and have 8 electrons in their outer shell, they are not reactive. when sodium and chlorine are combined to form sodium chloride (table salt), it is no longer dangerous. the number of valence electrons changes its reactivity and how it combines.

answer; natural resources;

the dependant variable is spilled water

the independent is the heat