Which of the following groups contain elements that are gaseous at room temperature?
a) alkali metals and alkaline earth metals
b) alkali metals and transition metals
c) noble gases and transition metals
d) noble gases and halogens

d) noble gases and halogens

Explanation:

Let's analyze each option to see which one is correct and which one is not:

a) alkali metals and alkaline earth metals --> FALSE

Alkali metals are the elements located in Group 1 of the periodic table. They are solid at room temperature.

Alkaline earth metals are located in Group 2 of the periodic table. They are also solid at room temperature.

b) alkali metals and transition metals --> FALSE

Transition metals are a group of metals found in the center of the periodic table. They are also solid at room temperature.

c) noble gases and transition metals --> FALSE

Noble gases are the elements in the Group 18 of the periodic table. They are elements that do not react with other elements. They are gas at room temperature.

However, transition metals are not gas, so this option is false.

d) noble gases and halogens --> TRUE

Halogens are the elements in the Group 17 of the periodic table. At room temperature, halogens exist in all the three states of matter, so also gas.

Therefore, this is the correct option.