Which is true about each element in a period or horizontal row of the periodic table? a. each element has one more outer shell than the element before it. b. each element has one more outer electron than the element before it. c. each element has one more isotope than the element before it. d. each element bonds with the element before it.

The answer is B as going from left to right on the periodic table elements increase by 1 in valence electrons

Valence electrons : The electrons on the outermost shell

the dissolution of polymer can be thermodynamically described in 2 steps.

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