Please see in action the famous games from the grandmasters demonstrating the combat dynamics of a Queen versus three minor pieces. No English language can explain the entire dynamics. You must see it for your self.
Generally speaking the queen is going to be better when the opponent's king is exposed to checks and/or when the position is "loose" ie pieces and pawns hanging, pawn weaknesses etc.
If the side without the queen can hold the position together and push a passed pawn there isn't really anything the queen can do.
For me I belive that the Queen is worth 3 pieces for a variety of reasons,
It combines the functionality of the Rook and the Bishop, the Bishop, which act like snipers in the early-mid game, are very valuable, because of their sniper-like capability, whereas the rook is bad in the early stages of the game, because the board is crammed usually, conversely, ...
I am presuming things such as pawns, bishops and knights count as minor pieces for what my answer will be.
Queen > 3 Minor Pieces
In the case that there is a way that you could get a checkmate, but you need to make a risk with what your opponent will notice and what he/she won't notice. You could try to put 3 pieces to get your opponent to take those ...
A lot depends on whether there are other pieces involved and the pawn structure.
If you mean positions with Q alone vs three minor pieces then relative king safety comes into play. The side with the Q tries to expose the opponents king and harass it.
The Q alone side may need to create connected passed pawns to make progress since the pieces should easily ...
The queen does a good job when there are a lot of weaknesses to attack, especially if the opponent's king is out in the open, so there are a lot of options for double attacks.
The pieces are generally stronger if they can coordinate and the king is still relatively safe. Earlier in the game that's usually the case.
It's a classic beginner's mistake to make a check for check's sake. You have to ask yourself what you have gained from that check? You basically allowed your opponent to develop one more piece. Their king will be safe after castling which you have helped speed up, and your Queen will be ripe for the picking. In essence you lost a tempo (due to you having to ...
I own the old books from Dr. M. Euwe, still the most comprehensive for chess opening moves. The 9th volume covers Scandinavian defense starting on p. 137; this variant is not mentioned. So I tend to agree that from a development standpoint this is a bad move
Qe5+ is not a blunder or a mistake but it is definitely inaccurate play. Qa5 (most popular line) keeps a check on 2 central squares as well as Qd8.
Defending with bishop
Also in the second line you mentioned (Bc2) after Bg4, white has an excellent move d5! Now white has a tempo in development, space as well as development whereas black is trying to ...
This is a bit trivial as an answer, but too long as a comment. You claim that you can develop "as good as White" but that is simply not true. White begins by interposing the Bishop 4.Be2. You play 4..Bg4. It is now a mistake to play 5.Nf3 because 5..Bxf3 spoils whites Pawns and makes his King insecure. But 5.d4! also gains a development tempo, and forces ...
The 3. .. Qe5+ is not a great continuation for black. Because:
It does not threaten anything really. White can block with developing (!) a bishop: 4. Be2.
It places blacks Queen in the center very early in the game where it will be a target of the attack for many whites pawns and pieces. Square e5 is far from a permanent position for the black queen, and ...
But why it's a bad move?
You are moving your queen to a square where it is going to be attacked again soon and then you will have to move the queen for a third time. Meanwhile white is developing fast and you have no pieces developed.
Moving your queen next to your king and moving your king in a diamond around your queen for up to 30 moves seems like it’d be decently fast and not need much thought if you’re really low on time. Every move up to and including the draw is as short as possible, distance-wise.
can I force a draw if I am running out of time?
Of course! Just swap the queen for the rook.
There are two basic possibilities.
He keeps the king and rook very close (normal best practice when trying to draw this difficult endgame). In that case every time you threaten the rook with your queen he must move the rook and keep it close to the king. It should ...