What makes an element withstand being exposed to a vacuum? Is it purely metallic elements?

What properties help an element to withstand a vacuum.
Because non metallic element such as h2o boils in a vacuum and metals don't.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).