Alessandro needs the following hardware to use his desktop computer for video chatting with his mother:

• Webcam : To capture his video so his mother can see him. A webcam with at least 720p resolution is recommended for clear video quality, with 1080p (Full HD) preferred for better clarity

• Speakers : To hear his mother during the video chat

• Microphone : To transmit his voice. This can be a built-in microphone on the webcam or a separate microphone. For everyday video calls, a basic unidirectional mic-equipped webcam is sufficient

• Monitor : To see his mother’s video feed clearly

• Computer with sufficient processing power and RAM : Ideally a desktop with at least an Intel Core i5 or equivalent processor and 8GB of RAM to ensure smooth video streaming and multitasking during the call

In summary, Alessandro should have a webcam, speakers, a microphone (often integrated with the webcam), and a monitor connected to a desktop computer with adequate processing power and memory to accomplish video chatting with his mother.