if boron loses 3 electron why it is non metal?
Answers
Boron is a chemical element Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth's crust and it non metal
Being a metal doesn’t simply depend on the number of valence electrons. It requires the element (or alloy/compound) to have the properties of a metal, including being conductive.
The factor for being conductive is whether the electrons are easy to separate and, in particular, how far apart the valence band is from the conduction band.
This is due to the small size of boron as the electrons are closer to the nucleus, so the attractive force is stronger. This isn’t an issue for lithium and beryllium, since those elements have a slightly lower effective nuclear charge reflected in their larger size which means the valence electrons are further from the nucleus than for boron.