Question

1. the periodic table organizes elements into columns called groups. for example, copper (cu), silver (ag), and gold (au), metals useful in jewelry making are all found in group 11. helium (he), neon (ne) and argon (ar), colorless nonreactive gases are found in group 18. why are elements arranged in groups in the periodic table? a) they are organized according to when they were discovered b) they are organized in groups according to the size of their atoms c) they are grouped in a column because they have similar properties d) they are arranged in columns by the number of protons in their atoms

Explanation:

The periodic table groups elements based on their properties. Elements in the same group share similar chemical properties. For example, Group 11 elements (Cu, Ag, Au) are metals useful in jewelry making, and Group 18 elements (He, Ne, Ar) are colorless nonreactive gases. Option a is incorrect as discovery time isn't the basis. Option b about atom size isn't the main reason. Option d refers to atomic number (protons) which arranges elements in periods (rows), not groups (columns).

Answer:

C. They are grouped in a column because they have similar properties