Answer:
protons : 10
electron : 10
neutron : 10
Explanation:
Protons will usually be the same as the electrons when its a <u>Atom</u> (when its a ion or covalent bond or simple bond they will most likely be different)
the atomic number represents protons and electrons
the mass number - the atomic number = neutron
Explanation:
Hi for this one u just need to remember and use the equation.

then u find mr of potassium which is 39.1.
then u do

you get the answer as 0.5115 write ur answer to 3 significant figures which will be 0.512 moles .
hope this helps :)