100.0 mL of 10.0M KCl solution is diluted to form 200.0 mL of a weaker solution. What is the concentration of the new, weaker solution?

What is the chemical formula of the following compound

Which element would mostly likely have an electron affinity measuring closest to zero

Element j is 1s 2s 2p 3s . (i) how many unpaired electrons does j have? (ii) is j a good oxidizing agent or a reducing agent? (iii) state reason for the answer.