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-

260 miles per hour

explanation:

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.