How does the energy of core electrons compare with the energy of valence electrons?

The energy of the valence electrons is greater than the energy of the core electrons

1. The energy difference between core electrons and valence electrons is different since it would require high amount of energy to lose electron from the core shell compared to the valence shell.

2. The electrostatic attraction between the varies. The closer the electron is to the core (nucleus) the more it experiences a strong nuclear force which in turn weakens the valence electron. During the process, the core electrons shield the valence electrons from exposure to nuclear force and hence easily lost during chemical reactions.

3. Core electrons only participate during nuclear reactions while valence electrons are responsible for chemical reactions through exchange of electrons between atoms.

petroleum? coal maybe?

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-