SQLite and tables?

Question

Database design

Good day to all!
There is a SQLite DB in it I create the table.
Can you please tell me if the approach is correct as shown in the screenshot?
Also of interest are the following:
1) the value of a NULL cell will or will not affect performance;
2) whether optimization becomes more complicated in the presence of NULL;
3) does NULL affect the search for values ​​and their sorting;
In printsepe, I can break this table into 2. and then there will be no holes with NULL, but does that make sense.

Answer 1

Thanks everyone.
Issues resolved independently.
For those who are interested, here is a link that helped solve my questions.
https://habrahabr.ru/post/127327/
The topic can be closed.