11. A chemical reaction happens when chemicals combine to form a new

substances

Explanation:

A chemical reaction happens when substances break apart or combine to form one or more new substances.

^Hope it helps, Hazel^

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

1.solid

2.carbon dioxide

3.helium