Use Mendeléev’s Periodic Table to predict the formulae for the oxides of the following elements:
K, C, AI, Si, Ba.

Explanation

To predict the formulae for the oxides of the elements K (Potassium), C (Carbon), Al (Aluminum), Si (Silicon), and Ba (Barium) using Mendeleev’s Periodic Table, we will follow these steps:

### Step 1: Determine the Group and Valency of Each Element
- **Potassium (K)**: Group 1, Valency = +1
- **Carbon (C)**: Group 4, Valency = +4
- **Aluminum (Al)**: Group 3, Valency = +3
- **Silicon (Si)**: Group 4, Valency = +4
- **Barium (Ba)**: Group 2, Valency = +2
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