What is the fourth largest element on the periodic table

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

Asa choose the correct set of reaction coefficients to properly balance the following chemical equation according to the law of conservation of mass: __s8 + __o2 ==> __so2 1, 1, 8 1, 8, 1 1, 8, 8 8, 1, 1

Can someone me with 6 to 10 plz this is for masteries test.