Question

Reference to the long form of the periodic table fills in the blanks with appropriate words.

The second and the third period have -------- elements and are called --------- periods.

• A. eight
• B. short

Answer 1

Modern periodic table:

• The modern periodic table is an arrangement of all the elements known in accordance with their increasing atomic number and recurring chemical properties.
• It is a tabular display of 118 chemical elements which consists of horizontal rows called periods and vertical columns are called groups.
• The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon.
• The third period contains eight elements: sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, and argon.
• Both these periods are short as they have only eight elements.

So the second and the third period have eight elements and are called short periods.