An atom of the same element that differs by the number of neutronsa) anionsb) cationsc) element d) isotope e) atom

Explanation:

All atoms of a same element have equal number of protons (atomic number) but may differ in the number of neutrons.

The atoms that differ in the number of neutrons are named isotopes.

For example: carbon-12 and carbon-13 are diferent isotopes of the same element, carbon. They have the same number of protons (6, which is the atomic number of carbon). On the other hand, while carbon-12 has 6 neutrons, carbon-13  has 7 neutrons.

As per the other choices:

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

the answer is symmetrical : )