Round 237.95 to four significant figures

Which other elements contain the same number of outer electrons as sodium

Define dew point. i am writing this part to be able to ask the question

Consider the reaction: n2(g) + o2(g) ⇄ 2no(g) kc = 0.10 at 2000oc starting with initial concentrations of 0.040 mol/l of n2 and 0.040 mol/l of o2, calculate the equilibrium concentration of no in mol/l how would this be done?