That's because you initialized the drive in GPT style and those extra partitions are automatically created. These partitions are small. There will also be an even smaller unformatted reserved partition which is not shown in Windows Disk Management but can be seen in third-party partitioning tools.
If you really want to reclaim those partitions, there are two things you can do.
- Run Diskpart from the command line and use the 'Clean' command to return the disk to its initial unpartitioned state. Then initialize it as MBR with Diskpart or Disk Management.
- Use a third-party software to delete those small partitions and add the unallocated space to the main partition. I use MiniTool Partition Wizard but there are others.
CORRECTION!!
The disk you've shown is not the new 1TB drive. It's the existing 512GB drive. You should not mess with that. Those partitions are essential for booting your system.