The mass number of a neutral atom of potassium (z=19) is 40 how many electrons does it have?

which characteristic of the nuclear force explains why the helium nucleus is exceptionally stable?

Explanation:

Two

The nuclear force does not work

under long distances

is greater in strength the the electomagnetic force when the distances are small.

I'm not sure what D means.

I think it does depend on charge.

You have to choose D but this is a notes question and I'm not at all certain of the answer.

One

If its number is 19, the the number of protons = the number of electrons = 19

Answer B

co2reflects heat radiation back to earth buning coal and oil emits co2 globe warms

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2