Question

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

Answer 1

The group that contains elements that are gaseous at room temperature are noble gases and halogens. Noble gases include helium, neon, argon, krypton, xenon, and radon, and halogens like fluorine and chlorine are gases under standard conditions. So the correct option is D.

Step-by-step explanation:

The question at hand involves identifying which groups of elements are gaseous at room temperature. Of the options provided, d) noble gases and halogens contain elements that are gaseous at room temperature. Noble gases, which include elements like helium, neon, argon, krypton, xenon, and radon, are all gases under standard conditions. Halogens such as fluorine and chlorine are also gaseous at room temperature. Alkali metals and alkaline earth metals are solid at room temperature. Furthermore, most transition metals are also solid at room temperature, with mercury being an exception as it is liquid.

To define the subject for the questions based on the examples given, we can use the keywords: alkali metal, halogen, noble gas, and alkaline earth metal as they relate to the classifications on the periodic table. The given examples classify elements like lithium as an alkali metal (Group 1), argon as a noble gas (Group 18), and chlorine as a halogen (Group 17), which are key aspects of elementary Chemistry covered in high school.

Answer 2

d) noble gases and halogens

Step-by-step 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.