The https scheme represents HTTP-over-TLS 1)
HTTP is a application protocol (OSI level 7) that is build on TCP as transport layer (OSI level 3)
HTTPS is essentially HTTP after the connection has been secured with TLS (ie SSL, ie TCP with SSL) (ie when the SSL handshake (negotiation) has succeed).
Chrome:
The port is 443.
See How to enable SSL on a server (ie HTTPS on a web server) ?
To make https mandatory for a website, set the Strict Transport Security (HSTS) header