Number of protons are equal to the number of electrons

Explanation:

the no of proton of an element is found in the inner part of the orbital of an element along with the neutron ,also knowing that this two add up to give mass no an element

where neutron+proton=mass no=nucleon no,where proton= electron, unless it carries charges call ion

no

sodium is solid at rt

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me