What does it mean if an element has 8 valence electrons

What if? physicists often measure the momentum of subatomic particles moving near the speed of light in units of mev/c, where c is the speed of light, and 1 mev = 1.6 ✕ 10−13 kg · m2/s2. based on this, what are the units of momentum for a high-speed subatomic particle in terms of fundamental si units?

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

In a set amount of time, a battery supplies 25j of energy to an electric circuit that includes two different loads. one of the loads produces 10 j of heat energy during this time interval. how much heat energy is produced by the second load in this time? explain your answer