What is the relationship between number of electrons on the outer energy levels and
groups?

Every element in a given group has the same number of valence electrons. For elements in the main groups (1-2, and 13-18), the number of valence electrons increases when moving from left to right along any period (row). The noble gases contain a full valence electron shell, which consists of eight electrons.

Explanation:

Hope this helps.

Valence Electrons

Explanation:

Say you are looking at a neutrally charged carbon atom, it has 6 electrons. The first electron shell can hold 2 electrons. The next can hold 8, the next can hold 8 and the next can hold ten and so on... Well in the Carbon atom case, it has 6 electrons, 6-2 is 4, so the carbon atom at 4 valence electrons, which actually helps it in making organic molecules, which in turn also helps make something you might have heard of before, organisms, the best example being, humans

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.