Lemon-garlic Chicken And Vegetables

• 4 zucchini
• 3 onions quartered (red)
• 1 black pepper (fresh ground)
• 1 bunch broccoli spears (cut into)
• 1 bell pepper in (red cut)
• 1/4 lenthwi
• 525 gr chicken breast without skin (halves)
• 16 ml vegetable oil divided
• 8 gr garlic (minced)
• 4 gr salt divided