Draw a shell model for boron identify the core and valence electrons

The picture below, I've drawn on Paint. I apologize for the crudeness of the model, but I think it will work. As you can see, this image shows the placement of the core, and of the valence electrons.

Knowing the valence electrons are always the outermost shell of electrons, and that electron shells carry an order sequence of 2, 8, 18, etc., The outermost electrons are 3.

Therefore, the Valence Electron count is 3.

Now for the core, it's important to note that it's the center of the atom, the middle. It contains all of the protons and neutrons in the atom, maintaining balance.

If you are required on an assignment to draw this, please make sure to draw the electrons in the correct order. 2, then 3.

I hope this helped!

Thanks!

Your friend in answering,

~Steve

i have no clue hope you find the answer

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.