This is not a good idea as stocks are volatile.
Step-by-step explanation:
One must never invest a lot of money in only one stock as the stocks are wont to change over time and gain or lose value.
If one wants a long term investment with at least some amount of safety they must be investing in stocks that grow consistently and then to break up the capital in small chunks and then invest them.
All of these can be invested in different shares in the market and then the shares would be more safe.
Even if one or two shares fall the others will be safe.