Which electrons participate in chemical bonding?

Covalent bonds
occurs between 2 metals or two non metals

for example

h2o H is hydrogen and o is oxygen there both non metals so there call covalent bonds
if u look at the periodic table it will show u a line at the right those are non metals and rember H is non metal even if it's on the other side of the chart.

It’s actually still in the u.s.

You can drink laxative, or  do this exercise when you are sitting in the bathroom on the toilet. to relieve  constipation  fast or in about 1 minute, pinch your nose after your usual exhalation. start holding your breath. but do not mouth breath during this just hold your breath.