What is meant by valency of an element ? give an example

valency of an element is a combining power of an element.

for example oxygen has six valance electron but its valency is 2.

hope it helps.

the answer is a. co2, this would be colder than the : )

explanation:

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).