What is the great thing about Bc4 here?

Question

Please forgive my blindness! I am a beginner and have not played in months.

I was going to go Bd3, where my bishop would have been protected by a pawn and poised to strike one of the next potential locations of the black knight. Instead, the app recommends Bc4, where I am hanging and it seems like the black queen could easily pressure me.

Can anyone enlighten me?

Answer 1

On d3 the bishop prevents the d-pawn from moving, thus hindering both the development of the c1-bishop and fighting for the center. Speaking of fighting for the center, on c4 bishop is controlling a central square and is just more active (puts pressure on f7, for example).

There is no need to be afraid of the queen attacking the bishop - you will just move it to b3, for example. After all, black will have to spend a tempo to attack it. On d3 the bishop can also be attacked in the future, say with a knight or by the e-pawn.

Answer 2

Bd3 is an inaccuracy for the following reason:

1. First of all, you are hindering your development by putting in front of your d-pawn. You have to either play your b-pawn or remove the bishop to active your dark squared bishop.
2. Bc4 is much more active than Bd3, the bishop has much more mobility. The black queen cannot pressure you at all, which move do you think could be risky?
3. This is a classic Scandinavian position, there are tons of references on Google about it, the principles, the objectives, etc.