1. Identify three elements that form only one cation.

Identify three elements that form only one anion. Nitrogen, oxygen and alkali metal

Explanation:

i am going to put the answers in order i dint feel like typing it out so yeah

a

d

c

b

b

b

a

d

a

b

c

c

c

b

d

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).