Which statements about the structure of the periodic table are true? a. the periodic table has an irregular shape because it has more periods than groups. b. the inner transition elements are placed at the bottom of the periodic table for easy viewing. c. the periodic table has horizontal groups and vertical periods, giving it a regular rectangle shape. d. the distribution of electrons in energy levels is responsible for the shape of the periodic table. e. nonmetals take up more than half the area of the periodic table. more than one correct answer

Below are the statements which are true about the structure of the periodic table:

B: The inner transition elements are placed at the bottom of the periodic table for easy viewing.

D: The distribution of electrons in energy levels is responsible for the shape of the periodic table.

Explanation:

Point A:

As we know that in a periodic table there are 7 period s and 18 groups. So, the number of periods is evidently lesser than the number of groups. But the shape of periodic table is regular and rectangular so point A is false.

Point B:

The inner transition elements or -f block elements are put at the bottom for easy viewing. These are the elements that have the valence electrons only  in the f-orbital's. Therefore, they are placed separately at the bottom side of the table so that they can be easily viewed or studied from there. So, point B is true.

Point C:

If we talk about option C, then it is very clear and true that considering a rectangular shape of the periodic table, the groups are vertically arranged and periods are horizontally arranged, therefore it is false.

Point D:

Atoms of all elements have definite electronic distribution in different energy levels like s, p d or f. This is a very prominent feature of periodic tale that elements are divided in specific blocks, s, p, d and f based on their electronic configurations. Therefore, it is true.

Point E:

We also know that no. of metals in a periodic table are more than the no. of non metals like almost 91 out of 118 elements  are metals in periodic table. Therefore, the point E "Nonmetals take up more than half the area of the periodic table." is false.

Hope it helps!