Why is there a section cut out of the periodic table of elements?

Answer 1

See also the "Related Questions" link to the left of this answer: "Why are elements arranged as they are in the periodic table?" Once you've looked at the question above, read this: The gaps are due to the fact that the different electron orbitals (s, p, d, f) hold different numbers of electrons each. An s-orbital can hold at most 2 electrons, while a p-orbital can hold up to 6, a d-orbital can hold up to 10, and an f-orbital can hold as many as 14 electrons. In order to align the columns of the periodic table so that each element in the column has the same outermost (or valence) electron configuration, there need to be gaps. Actually, if you look at the modern periodic table, there is always a block of elements separate from the others (called the Lanthanides and Actinides, or the f-block elements) at the bottom. You can actually draw the periodic table with even bigger gaps is if you include those together with the rest of the elements. Drawing it this way is cumbersome because it is so long and narrow, but it is actually a better way to see the trends in the electron configurations. See the Web Links to the left for periodic tables that show the electron configurations of each element, as well as this funny looking stretched out version with the f-block elements all in the same table.
mendeleevs left the gaps for the elements that's hadnt been dicovered by then but he pridicted that more element can be discovered in the future and placed them according to their properties after a specific period.Some elements pridicted by mendeleevs were eka aluminum which we today call galium.Eka means an element with similar properties to that of aluminum and galium does have properties similar to aluminum.

Answer 2

The section cut out of the Periodic Table known as the f-block represents the lanthanides and actinides. Due to their size, they don't fit well in the main body of the table, so they are placed below to keep the table manageable in size.

Answer 3

You will not really find "holes" in modern periodic tables of the elements. However, to explain why older tables did indeed have holes requires a little bit of history:

When scientists first began really probing the secrets of the atom, and began to understand how they were formed and under what natural laws, certain patterns emerged. These patterns included things like the weight of the nucleus, the number of electrons and so on.

The periodic table was then filled in according to those laws and elements were filled in. However, there were many cases where we thought there should be an element present, but we had not yet discovered it (or, as in the case of some of the latest additions to the table, we actually had to create these elements in a laboratory). As more information came in, scientists realized that there initial ideas were indeed correct and the holes have since been filled in.

Answer 4

There is a section cut out of the Periodic Table of Chemical Elements just for the fact that all of it wouldn't fit, so it got put down under but should still be pictured as being part of groups 6 and 7

Answer 5

for future additions hat will be discovered

Answer 6

they are artificially made elements added to the periodic table

Answer 7

because those elements were not discovered at that time

Answer 8

Because the element with atomic number is not yet discovered.

Answer 9

The holes or gaps represented undiscovered elements. These were discovered later.

Answer 10

He observed that the elements properties do not fit on a column in some cases and assumed that a new element must be interleaved, not yet discovered in his time.