What is the name of the compound Si₉Br₃?

In the following table, all the columns for the element calcium are filled out correctly. element electron structure of atom electron structure of ion net ionic charge calcium 1s22s22p63s23p64s2 1s32s22p63s23p64s1 +1 true false

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

Which of the following units is not an official si unit