What property of an element does the group number identify in a numbering system that uses "a" and "b"?

What is the correct lewis structure for chloroform chcl3

Answer explain why it is not possible to deduce a complete order of reactivity.

The human activities in two locations are described below: location a: rampant use of plastic containers location b: excessive use of pesticides and fertilizers which statement is most likely true? location a will have poor air quality because plastic is biodegradable. location a will experience water scarcity because plastic absorbs moisture. the population of honeybees will increase in location b because production of crops will increase. the population of fish in location b will decrease because the water is contaminated.