Is the night sky divided into contellations? is a light-year is a measurement of time?

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

Adilute aqueous potassium nitrate solution is

What is the chemical name of the compound na2co3? use the list of polyatomic ions and the periodic table to you answer. a. sodium carbon oxide b. sodium carbonate c. sodium(ll) carbonate d. sodium oxalate