Only correct answer ... not for points .
with explaination .
the diameter of rectangular box are in the ratio 2:3:4 and difference between the cost of covering with sheet of paper at the rate of ₹4 and ₹4.50 per m² is 416 . Find the dimension of box .​

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.

Jean-baptiste lamarck

Answer: 1s²  2s²  2p⁶explanation: from the periodic table, we can note that the neutral fluorine  has 9 electrons (symbol is shown in the attached image)therefore, the configuration of neutral fluorine  is: 1s²  2s²  2p⁵now, f⁻  means that the neutral fluorine  gained one extra electron. this means that f⁻  has 10 electrons.the extra electron will occupy the 2p level to make it complete.the configuration now  is: 1s²  2s²  2p⁶comparing between both f and f⁻, we can note that f⁻  has now complete orbitals which means that it is more stable than f based on lewis postulatehope this : )