How many protons are in the radioactive isotope 40/19k?

19 protons are present in the given isotope.

Explanation: We are given a radioactive isotope and we need to find the number of protons in this isotope.

General representation of isotopes are given as:

Where, Z = Atomic number = Number of protons = Number of electrons

A = Atomic Mass = Number of protons + Number of neutrons

X = Element

In the given element K, Atomic number is 19 and mass number is 40.

As Z = 19,

Number of protons in given isotope = 19.

i think   the answer is c hope i'm right

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.