1a, 3b, and 7a are examples of on the periodic table.

1 A, 3 B, and 7 A are examples of  group number on the periodic table.

Explanation:

The table that consists of elements arranged systematically on the basis of atomic numbers is called periodic table. Groups and periods are two important part of a periodic table. A periodic table contains seven horizontal rows, called as periods and 18 vertical columns, called group.

The groups name is given in the form of number and alphabets. It represents the columns present in the  periodic table.

Hence, 1 A, 3 B, and 7 A are examples of  group number on the periodic table.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2