These electron configurations are NOT valid, determine what is wrong with them: 19) 1s2 2s2 2p6 3s2 3p6 4s2 4d10 4p5

20) 1s2 2s2 2p6 3s2 3d5

21) [Ra] 7s2 5f8

22) [Xe]

|>GIVING BRAINLIEST<|
-WORTH 15 POINTS-

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min

3. dark matter

empty space could also be a simple vacuum