The ID for Iron Blocks is 42.
To craft a block of gold, you need 9 gold ingots. Go in a crafting table and put 1 gold ingot on each slot. You can craft the block back into ingots by putting it in the table.
the item ID for gold is 14
Gold ingot = 266
A minecraft block is 1 Meter to scale in real life.
The hardest block in Minecraft is bedrock. It is completely unbreakable unless on creative mode.
There is no command block in minecraft. If you go to the Minecraft WiKi it will have all the information you need for anything in the game.
You can place a block in Minecraft by right clicking on a block besides air while it is in your hand.