Tone is the writer's attitude toward the material. Tone may be playful, formal, intimate, angry, serious, ironic, outraged, baffled, tender, serene, depressed, etc.
Sc I, the tone starts out formal, with Macbeth talking to Banquo about his travel plan, but ends up serious and angry. By the end of the scene, the plan to kill Banquo and Fleance is set in motion.
Sc II- Serious, Macbeth shrugs off Lady Macbeth's question about his plans. He is tender towards her, trying to protect her from his murderous plans.
Sc III- Serious, Banquo is murdered, Fleance escapes, ironic.
Sc IV- Macbeth tries to be playful at his first banquet as King, but is haunted by Banquo's ghost, he ends up sounding baffled, outraged, and it is ironic, that a ghost unseen by his guests, manages to shatter Macbeth's demeanor and make him appear to be crazy, or an unfit King.
Sc V - Hecate appears, the tone is serious, as she plots Macbeth's demise.
Sc VI- Lennox knows the truth about Macbeth, the tone is very serious. The fate of Scotland is discussed, the hope that Malcolm can seize it back from the tyrant Macbeth.
I will not tell you the tone, but rather how to figure it out for yourself.
To determine the tone fore each scene, first look at Shakespeare's word choice, or diction. Notice if any words or phrases are repeated, or what the strongest words in the scene are. Then determine the connotations of those words. How do they make you feel? This is most likely the tone of the scene.
You can also look at the imagery and the setting to determine tone. Because Macbeth is a play, Shakespeare would have ensured that the setting contributed to the overall feel of the scene. Is it raining or sunny? Are there clouds? Is the stage crowded or sparse?