Question

What is the name for the horizontal rows of the periodic table?
$
  {\text{A}}{\text{. Groups}} \\
  {\text{B}}{\text{. Periods}} \\
  {\text{C}}{\text{. Families}} \\
  {\text{D}}{\text{. Sets}} \\
$

Answer 1

Hint: To find the answer we refer to the definitions of a periodic table and each of the given options to pick the correct choice appropriately.

Complete step by step answer:
Groups – A set of elements occupying a column in the periodic table and having broadly similar properties arising from their similar electronic structure.

Periods - A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Arranged this way, groups of elements in the same column have similar chemical and physical properties, reflecting the periodic law.

Families - A family is a column of elements in a periodic table in which elements are arranged into a group based on the similarity with similar chemical properties. Examples: Group 18 on the periodic table is also known as the noble gas family or noble gas group.
Sets - A set is a group or collection of objects or numbers.

Periodic table - a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns. The horizontal rows in the periodic table are periods, while the vertical rows are called groups.
So, the correct answer is “Option B”.

Note: In order to answer this type of question the key is to know the definitions of all the given terms in the question.
Periodic table is a tabular display of the chemical elements, which are arranged by atomic number, electron configuration, and recurring chemical properties. The columns, called groups, contain elements with similar chemical behaviors.
To summarize, the periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.