#### Answer

HR: Group 17
H$_2$R: Group 16
H$_3$R: Group 15

#### Work Step by Step

HR: Group 17
-The oxidation state for hydrogen is 1+. If hydrogen is chemically combined with a group 17 element, which has an oxidation number of 1-, then we will have a 1:1 relationship between the two elements. Therefore, we can write the general formula for hydrogen combined with a group 17 element as HR, with the R representing the group 17 element.
H$_2$R: Group 16
-The oxidation state for hydrogen is 1+. If hydrogen is chemically combined with a group 16 element, which has an oxidation number of 2-, then we will have a 2:1 relationship between hydrogen and the group 16 element. Therefore, we can write the general formula for hydrogen combined with a group 16 element as H$_2$R, with the R representing the group 16 element.
H$_3$R: Group 15
-The oxidation state for hydrogen is 1+. If hydrogen is chemically combined with a group 15 element, which has an oxidation number of 3-, then we will have a 3:1 relationship between hydrogen and the group 15 element. Therefore, we can write the general formula for hydrogen combined with a group 15 element as H$_3$R, with the R representing the group 15 element.