Please help me. Please help me. ​

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

Which statement is true if the refractive index of medium a is greater than that of medium b? a. total internal reflection is possible when light travels from air to medium b to medium a. b. total internal reflection is possible when light travels from medium a to medium b. c. total internal reflection is possible when light travels from medium b to medium a. d. total internal reflection is possible when light travels from air to medium a. e. total internal reflection is possible when light travels from air to medium b.

When a pair of 10-n forces act on a box of candy, the net force on the box is a 20 n. b about 14 n. c zero. d any of the above depending on the directions of forces.