Which is a property of potassium (K)? O A. It is dull and brittle. O B. It is not reactive. O C. It is white and hard. O D. It is extremely reactive.

D. It is extremely reactive.

Explanation:

Potassium has atomic number of 19 and belongs to the group 1 elements.

A. It is dull and brittle

This is not true as potassium is a metal with a silver lustre.

B. It is not reactive

This is false. Because it is a group 1 element, it would readily lose it's electron to achieve octet configuration making it a reactive metal.

C. It is white and hard.

Potassium is a white metal, however it is not hard. Rather it is soft.

D. It is extremely reactive.

This is correct. Because it is a group 1 element, it would readily lose it's electron to achieve octet configuration making it a reactive metal.

d.) the average kinetic energy of the gas particles is greater in container b because its particles move faster.