how to close google chrome and have it save your tabs

In the settings, there is an option that says "Continue where you left off" under "On Startup" option. That should keep your tabs intact when you close and launch chrome every time.

This will work for both the hotkey and manual close.

On a Mac (MacBook Pro) Use the "command --> Q" shortcut or click on your screen's top-left menu option "Chrome --> Quit Google Chrome" or from your Dock (typically at the bottom of your screen) right-click on the Chrome icon then choose Quit. Any of these will preserve your tabs. That is... if you have already selected the Chrome option to 'Continue Where I Left Off'.

Using the Red 'X' icon at the top-left of your Chrome browser window, to close the browser, will not preserve the tabs.