Which of the following is the family that contains the least reactive elements? (A) Alkali metals. (B) Alkaline earth metals. (C) Transition elements. (D) Halogens. Or (E) noble gases.
The periodic table is a diagrammatic arrangement of all the elements that matter is composed of. The elements are arranged into horizontal rows called periods and vertical columns called groups. The periods are numbered one to seven with the very bottom two rows, the lanthanides and actinides, fitting in where the star and triangle are located. The groups are numbered one to 18, usually written with Roman numerals. It has taken scientists several 100 years to draw up the periodic table that we currently use.
Elements have been arranged into these specific periods and groups according to a number of factors. These include the manner in which the elements react, their atom size, number of protons, and so on. Metals tend to be located on the left and nonmetals on the right, with a stepped line of metalloids separating the two. Metals tend to react in a similar manner. Nonmetals tend to react in a similar manner. And the metalloids tend to react in a similar manner.
The colors on this periodic table show a bit more detail on how different families of elements react in a similar manner. Group one, the alkali metals, all react in a similar way. Note that although hydrogen is not a metal, it is placed in the same group because it has the same pattern of behavior when reacting. The other families of the periodic table where elements exhibit similar behavior when reacting are the alkaline earth metals in group two, the d-block in groups three to 12 which contains the transition elements, and the f-block containing transition elements. The p-block metals, the metalloids, the group 14 to 16 nonmetals, the halogens in group 17, and the noble gases in group 18.
Individual atoms of elements do not exist in nature. All elements will react with atoms of the same element or other elements to become stable. The only exception are the noble gases. Noble gases do exist as single or monoatomic atoms in nature because they are highly stable. Noble gases do not generally react. However, the noble gases can be induced to react under special conditions such as very high temperatures and pressures. So, the family that contains the least reactive elements is (E), the noble gases.