So i have to say the techdroider render of the Pixel XL is likely wrong, considering it has essentially 0 bezel, I assumed some minor bezel when I synced up the sizes. But given the data available, and assuming the screen sizes are correct (Pixel 5.0, Pixel XL 5.5) then this should be pretty close.
Valency, the combining capacity of an element, is equal to the number of electrons needed, or required to be removed from the outermost shell of the atom of that element, to have a complete 'octet'. The helium atom has only the 1s orbital in its only shell, and it is completely filled with 2 electrons. Its electronic configuration is 1s2. Therefore, helium and the other inert gases with complete octets normally do not take part in chemical reactions. They are considered as zero-valent elements.
Boron has three valence electrons. It is in group 13. 1st energy level ------- 2 e-. 2nd energy level-------8 e-. 3rd energy level ------3 e-. Outermost energy level is the the 3rd energy level and it has three electrons. Valence electrons are the electrons in the last energy level of an atom.