Match the following families with their properties. There are two properties for each family. alkali metals
alkaline earth metals
halogens
noble gases

1 valence electron
very reactive nonmetals
reactive metals
7 valence electrons
8 valence electrons
very little reactivity
very reactive metals
2 valence electrons

alkali metals: 1 valence electron, very reactive metals

alkaline earth metals: 2 valence electrons, reactive metals

halogens: 7 valence electrons, very reactive nonmetals

noble gases: 8 valence electrons, very little reactivity

Explanation:

The groups increase by 1 valence electron as you move from left to right across the periodic table, skipping over the transition metals. The closer an element is to having a full octet of 8 valence electrons, the more reactive it will be. The alkali metals and halogens are both just 1 away from an octet -- alkali lose an electron, halogens gain one. This makes them very reactive.

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.