Can someone please describe what they’re seeing in this picture?

In the given figure, There are two atoms -

sodium has one electron in valence shell and to get noble gas configuration ( stability ) it need to donate the outer most electron.

whereas,

chlorine has 7 electrons in valence shell and to get noble gas configuration ( stability ) it need to get one more electron.

in this condition Na ( sodium ) donates it's outermost electron to Cl ( chlorine ) and both became stable.

but now sodium has more number of protons than the electrons hence it get positive (+) charge and chlorine has more electrons than the protons hence it get negative (-) charge

so, they get stick to each other by strong electrostatic force acting on the charged atoms and forms a salt " NaCl " ( sodium chloride ) .

i hope it helped you

d.) the average kinetic energy of the gas particles is greater in container b because its particles move faster.