Question

A __________ or group of elements has similar properties.

Answer 1

Family!

Answer 2

Period. That's why its called the PERIODic Table.

Answer 3

It depends on the textbook the asker is using. My high school course emphasized families over periods. A period is a column of elements; a family is a group of elements with similar characteristics. Usually families coincide with periods anyhow, so the question depends on what the asker was taught.

Answer 4

I would venture to say, however, that "family" is more correct, since periods do not always contain elements of similar characteristics.