Answer:-
Solution:- It is a unit conversion where it asks to convert kg of He to atoms. We need to convert kg to grams, grams to moles and finally moles to atoms.
We know that, 1 kg = 1000 g
Molar mass of He is 4.0 grams per mole and 1 mole of an atom equals to Avogadro number of atoms.
The set up would be as given below:

= 
So, there are
of He in it's 536 kg.
Answer:
Explanation:
The neutral one has atomic structure 1s2 2s2
The one with a positive charge could be 1s2 2s which has lost one of its 2s electrons.
Answer:
moles = 36/180 = 0.2 moles
molarity = 0.2/2 = 0.1 mol/dm3
Z=1 is the formula i would have to see the following lol