# What are inner core electrons and how do they influence chemical and physical properties?

There are six groups of p–block elements in the periodic table numbering from 13 to 18. Boron, carbon, nitrogen, oxygen, fluorine and helium head the groups. Their valence shell electronic configuration is $\ce{ns^2 np^{1-6}}$(except for He).

The inner core of the electronic configuration may, however, differ. The difference in inner core of elements greatly influences their physical properties (such as atomic and ionic radii, ionisation enthalpy, etc.) as well as chemical properties

The above lines are from my school's textbook.

How does inner core electron create such differences and and what are inner core electrons?

• Core electrons are electrons that are not valence electrons. I am sure your textbook has something about periodic trends going down a group. Go and read it. – orthocresol Dec 7 '15 at 2:48
• Check out the differences between argon and krypton. Then extrapolate for other p-elements. – Jan Dec 15 '15 at 22:17