What is the nuclear charge for argon with 22 neutrons? ?

'Nuclear charge' is simply the elements atomic number and is always positive. So the information regarding argons number of neutrons is irrelevant. No matter which isotope of an element you are discussing, the 'nuclear charge' will never change. Therefore the answer is 18+. Now, if you are actually looking for the atomic charge you can find this by taking protons (atomic number) and subtracting number of electrons(for an element). To find charge of an ion you can easily refer to the periodic table where you may already know, group 1 is a 1+ charge, group 2 is a 2+ charge, etc. but in this case we are looking at Argon which is a gas so will not be ionic.  

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o