Which pair of atoms can form an ionic bond?
* na, k (sodium, potassium)
* k, f (potassium, fluorine)
* f, cl (fluorine, chlorine)
* na, ne (sodium, neon)

K, F (Potassium, Fluorine)

Explanation: Ionic bonds are formed by transfer of electrons between metal and non metals.

Covalent bonds are formed by sharing of electrons between non metals.

Electronic configuration of potassium:

Potassium atom will lose one electron to gain noble gas configuration and form .

Electronic configuration of fluorine:

Fluorine atom will gain one electron to gain noble gas configuration and form .

In potassium fluoride the one electron from potassium metal gets transferred to fluorine atom and thus form an ionic bond to give

distance, luminosity, brightness, radius, chemical composition, and temperature

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.