if a atom has 12 positively charged protons and 12 negatively charged electrons when is its total charge ?

The total charge in an atom is zero or it is neutrally charge. both nulify each others charge.

t= half of the arc subtended by t.

r= half of the arc subtended by r.  

t+r= half of the arc subtended by t + half of the arc subtended by r= half of 360=180

step-by-step explanation:

tayeserqp p201311