Determine the identity of x in the following alpha decay equation ( )

At-207 (meaning At with the number on the top left being 207 and the number at the bottom left being 85.

Explanation:

The sum of the mass numbers has to equal on both sides, so we need 211 = 4+a

a=207

The sum of the atomic numbers as to equal on both sides, so 87=2+b

b=85

The element is determined by the mass number.

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